U.S. patent application number 15/658027 was filed with the patent office on 2017-11-09 for regeneration of cathode material of lithium-ion batteries.
This patent application is currently assigned to UNIVERSITY OF CALCUTTA. The applicant listed for this patent is UNIVERSITY OF CALCUTTA. Invention is credited to Nilanjan Deb.
Application Number | 20170324123 15/658027 |
Document ID | / |
Family ID | 52479062 |
Filed Date | 2017-11-09 |
United States Patent
Application |
20170324123 |
Kind Code |
A1 |
Deb; Nilanjan |
November 9, 2017 |
REGENERATION OF CATHODE MATERIAL OF LITHIUM-ION BATTERIES
Abstract
Lithium metal oxides may be regenerated under ambient conditions
from materials recovered from partially or fully depleted
lithium-ion batteries. Recovered lithium and metal materials may be
reduced to nanoparticles and recombined to produce regenerated
lithium metal oxides. The regenerated lithium metal oxides may be
used to produce rechargeable lithium ion batteries.
Inventors: |
Deb; Nilanjan; (Kolkata,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF CALCUTTA |
Kolkata |
|
IN |
|
|
Assignee: |
UNIVERSITY OF CALCUTTA
Kolkata
IN
|
Family ID: |
52479062 |
Appl. No.: |
15/658027 |
Filed: |
July 24, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14464420 |
Aug 20, 2014 |
9748616 |
|
|
15658027 |
|
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|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C01G 51/085 20130101;
C01G 45/1221 20130101; C01D 15/04 20130101; Y10T 29/49115 20150115;
C22B 26/12 20130101; C01P 2002/82 20130101; C22B 7/00 20130101;
C01G 51/04 20130101; Y02P 10/20 20151101; C01G 51/42 20130101; Y02E
60/10 20130101; H01M 4/525 20130101; Y02W 30/84 20150501; H01M
10/54 20130101; C01G 53/42 20130101; C01P 2002/72 20130101; C01P
2006/40 20130101 |
International
Class: |
H01M 10/54 20060101
H01M010/54; C22B 26/12 20060101 C22B026/12; C01D 15/04 20060101
C01D015/04; C01G 53/00 20060101 C01G053/00; C01G 51/04 20060101
C01G051/04; C01G 51/08 20060101 C01G051/08; C01G 51/00 20060101
C01G051/00; C22B 7/00 20060101 C22B007/00; H01M 4/525 20100101
H01M004/525; C01G 45/12 20060101 C01G045/12 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 2013 |
IN |
962/KOL/2013 |
Claims
1. A method for producing lithium metal oxides, the method
comprising: forming a mixture of at least one lithium halide and at
least one metal oxide; reducing the lithium halide and the metal
oxide to respective nanoparticles of lithium and nanoparticles of
metal; and combining the nanoparticles of lithium with the
nanoparticles of metal in the presence of oxygen to produce
regenerated lithium metal oxide.
2. The method of claim 1, wherein the reducing of the lithium
halide and the metal oxide to the nanoparticles of lithium and the
nanoparticles of metal comprises contacting the lithium halide and
the metal oxide with at least one metal halide and a reducing
agent.
3. The method of claim 1, wherein the reducing of the lithium
halide and the metal oxide to the nanoparticles of lithium and the
nanoparticles of metal comprises contacting the lithium halide and
the metal oxide with the at least one metal halide and the reducing
agent comprises contacting at a temperature and for a period of
time sufficient for reducing the lithium halide to produce the
nanoparticles of lithium and reducing the metal halide and the
metal oxide to produce the nanoparticles of metal.
4. The method of claim 2, wherein the reducing agent is at least
one of hydrogen gas, carbon monoxide, sodium borohydride, lithium
borohydride, hydroquinone, hydrazine hydrate, calcium hydride,
sodium hydride, N-dimethylformamide, sodium citrate, or a
combination thereof.
5. The method of claim 2, wherein metal of the metal oxide is the
same as metal of the metal halide.
6. The method of claim 5, wherein the metal of the metal oxide is
at least one of Co, Mn, or Ni.
7. The method of claim 6, wherein the metal is Co and the metal
oxide is CoO, Co.sub.3O.sub.4, or a combination thereof.
8. The method of claim 1, wherein the reducing comprises reducing
the lithium halide to nanoparticles of lithium and reducing CoO and
Co.sub.3O.sub.4 to nanoparticles of cobalt.
9. The method of claim 1, wherein the combining is performed at
ambient temperature and under ambient atmospheric pressure.
10. The method of claim 1, wherein the lithium halide is lithium
chloride.
11. The method of claim 1, wherein the lithium metal oxide has a
formula Li.sub.xMO.sub.y, where M is one or more transition metals
each having a stable formal oxidation state of +2 or +3, and
(x+3-z)/2.ltoreq.y.ltoreq.(x+3+z)/2, where z is 0, 1, or 2.
12. The method of claim 11, wherein x is 1 and M is at least one of
Mn, Co, or Ni.
13. The method of claim 1, further comprising obtaining the at
least one lithium halide and the at least one metal oxide from a
partially or fully depleted lithium-ion battery by a method
comprising: recovering the lithium metal oxide from the lithium-ion
battery; and converting at least a portion of the lithium metal
oxide to the lithium halide and the metal oxide.
14. The method of claim 13, wherein the lithium metal oxide is
LiCoO.sub.2.
15. The method of claim 13, wherein the converting at least a
portion of the lithium metal oxide to the lithium halide and the
metal oxide comprises: oxidizing the lithium metal oxide to lithium
oxide and the metal oxide; hydrating the lithium oxide to lithium
hydroxide; and halogenating the lithium hydroxide to the lithium
halide.
16. The method of claim 15, wherein the oxidizing comprises heating
the lithium metal oxide under oxidizing conditions at a temperature
and for a period of time sufficient for oxidizing the lithium metal
oxide.
17. The method of claim 15, wherein the halogenating comprises
contacting the lithium hydroxide with a hydrohalic acid to
halogenate the lithium hydroxide to the lithium halide.
18. The method of claim 17, wherein the hydrohalic acid is at least
one of hydrochloric acid, hydrofluoric acid, hydrobromic acid, and
hydroiodic acid.
19. The method of claim 15, wherein the hydrating comprises
hydrating at a temperature and for a period of time sufficient for
decomposing the lithium oxide to lithium hydroxide.
20. The method of claim 15, wherein the hydrating comprises
hydrating in distilled water.
Description
[0001] This Application is a Divisional under 35 U.S.C. .sctn.120
of U.S. application Ser. No. 14/464,420 filed on Aug. 20, 2014,
which claims priority benefit under 35 U.S.C. .sctn.119(a) of
Indian Patent Application No. 962/KOL/2013, filed Aug. 20, 2013,
entitled, "Regeneration of Cathode Material of Lithium-Ion
Batteries," each of which are incorporated herein by reference in
their respective entireties.
BACKGROUND
[0002] Due to the high energy intensity, light weight, and long
service life, lithium-ion (Li-ion) batteries have become one of the
most popular types of rechargeable batteries for portable
electronic devices, military, electric vehicle and aerospace
applications.
[0003] Of the various lithium-ion battery types, Lithium cobalt
oxide (LiCoO.sub.2) is the most widely used cathode material for
commercial batteries. However, spent Li-ion batteries with this
cathode material are a concern for wastage of precious metals,
while disposal may cause pollution. Recycling of LiCoO.sub.2
cathode materials from spent lithium-ion batteries is therefore
desirable, including the separation and regeneration of LiCoO.sub.2
cathode materials. The current processes involving separation of
the elements into different fractions are not effective in terms of
cost and energy requirements.
SUMMARY
[0004] Lithium metal oxides may be regenerated under ambient
conditions from materials recovered from partially or fully
depleted lithium-ion batteries.
[0005] In an embodiment, a method for regenerating a cathode
material from a partially or fully depleted lithium-ion battery may
include recovering lithium metal oxide from the lithium-ion
battery, and converting at least a portion of the lithium metal
oxide to lithium halide and a metal oxide. The lithium halide and
the metal oxide may be reduced to respective nanoparticles, and the
lithium nanoparticles may be combined with the metal nanoparticles
in the presence of oxygen to produce regenerated lithium metal
oxide.
[0006] In an embodiment, a method for regenerating and reusing
cathode material from a partially or fully depleted lithium-ion
battery may include recovering lithium metal oxide from the
battery, converting at least a portion of the lithium metal oxide
to lithium halide and a metal oxide, reducing the lithium halide
and the metal oxide to respective nanoparticles, and combining the
lithium nanoparticles with the metal nanoparticles in the presence
of oxygen to produce regenerated lithium metal oxide. A metal foil
may be coated with the regenerated lithium metal oxide, the coated
metal foil may be layered with separator sheets and an anode sheet
to produce a stacked electrode structure, and the stacked electrode
structure may be contacted with an electrolyte solution to produce
a lithium-ion battery.
[0007] In an embodiment, a method for producing lithium metal
oxides may include forming a mixture of at least one lithium halide
and at least one metal oxide, reducing the lithium halide and the
metal oxide to respective nanoparticles, and combining the lithium
nanoparticles with the metal nanoparticles in the presence of
oxygen to produce regenerated lithium metal oxide.
BRIEF DESCRIPTION OF THE FIGURES
[0008] FIG. 1 depicts a representation of a lithium-ion battery
according to an embodiment.
[0009] FIGS. 2A and 2B depict flow diagram representing methods for
regenerating lithium metal oxides according to an embodiment.
[0010] FIGS. 3A and 3B show comparative x-ray diffraction scans for
LiCoO.sub.2 regenerated according to an embodiment. FIG. 3A is a HR
XRD of regenerated LiCoO.sub.2. FIG. 3B is a XRD of LiCoO.sub.2
from other sources at 300.degree. C., 500.degree. C., and
700.degree. C.
[0011] FIGS. 4A and 4B show comparative FTIR scans for LiCoO.sub.2
regenerated according to an embodiment. FIG. 4A is an FTIR of
regenerated LiCoO.sub.2. FIG. 4B is an FTIR of LiCoO.sub.2 from
other sources.
[0012] FIGS. 5A-5D show voltammetry scans for LiCoO.sub.2
regenerated according to an embodiment. FIG. 5A is a LiCoO.sub.2
peak in the oxidation process of a cyclic voltammeter in DMSO at a
scanning rate of 100 mV/s. FIG. 5B is a LiCoO.sub.2 peak in the
reduction process of a cyclic voltammeter in DMSO at a scanning
rate of 100 mV/s. FIG. 5C is a cyclic voltammogram of regenerated
LiCoO.sub.2 in acetonitrile at a scanning rate of 100 mV/s. FIG. 5D
is a cyclic voltammogram of regenerated LiCoO.sub.2 in acetonitrile
at a scanning rate of 100 mV/s.
DETAILED DESCRIPTION
[0013] A representation of a cylindrical lithium-ion battery 10 is
schematically depicted in FIG. 1. A lithium-ion (Li-ion) battery
may include a cathode active material that is a composite of
lithium and a transition metal such as manganese (Mn), cobalt (Co)
or nickel (Ni) for a cathode plate 11, and a lithium intercalating
anode active material of carbon, such as graphite or amorphous
carbon, for an anode plate 12. The cathode plate 11 and the anode
plate 12 may be stacked together with a separator material 13
disposed therebetween so that the cathode plate and anode plate are
not in direct physical contact with each other. The separator
material 13 may be, for example, a finely porous insulating
material that may, for example, be a resin such as polyethylene
(PE) or polypropylene (PP), a laminate thereof, or inorganic
compounds such as alumina in the dispersed form. A separator film
may have a thickness of, for example, about 15 .mu.m to about 50
.mu.m.
[0014] In an embodiment, a cathode plate 11 may be prepared as
described below. A cathode active material for Li-ion batteries
may, in general, be a lithium metal oxide represented by the
formula Li.sub.xMO.sub.y, where M is one or more transition metals
each having a stable formal oxidation state of +2 or +3, and
(x+3-z)/2.ltoreq.y.ltoreq.(x+3+z)/2, where z is 0, 1 or 2. In an
embodiment, M may be Mn, Co or Ni. As mentioned above, a commonly
used lithium metal oxide is LiCoO.sub.2. A powder of the cathode
active material and a conductive agent may be mixed thoroughly. As
examples, the conductive agent may be graphite type or amorphous
carbon powder. In an embodiment, the conductive agent may be about
7 weight % to about 25 weight % of the cathode active material. A
solution of a binder, such as polyethylene glycol (PEG) or
polyvinylidene fluoride (PVDF), for example, in a solvent, such as
N-methylpyrrolidone (NMP), may be added to the above mixture, and
the components may be mixed together to form a slurry. The polymer
binder may be any binder generally used in Li-ion batteries.
Another example may include hexafluoropropylene (HFP).
[0015] In an embodiment, the slurry may be coated on a first side
of a foil, such as an aluminum foil having a thickness of about 10
.mu.m to about 20 .mu.m, and dried at an elevated temperature, such
as about 80.degree. C. to about 100.degree. C. Using the same
procedure, the slurry may be coated on the second side of the foil
and dried. Subsequently, the coated foil may be compression molded
by a roll press, and cut into a predetermined size to prepare the
cathode plate 11. In an embodiment, the foils may be cut prior to
coating.
[0016] In an embodiment, an anode plate 12 may be prepared as
described below. An anode active material for Li-ion batteries may,
in general, be a metal, for example, lithium, carbon, or a material
capable of intercalating lithium or forming a compound. Carbon
materials may include, for example, graphitic material or amorphous
carbon material. The material capable of intercalating lithium or
forming a compound may include, for example, metals such as
aluminum, tin, silicon, indium, gallium, and magnesium, alloys
containing such elements, metal oxides such as of tin and silicon,
composite materials of the metal, alloy or metal oxide, and a
graphitic or amorphous carbon material.
[0017] In an embodiment, a carbon material may be used for the
anode active material. A solution of a binder, such as PVDF, for
example, may be dissolved into a solvent, such as NMP, for example,
and the anode active material may be added to form a slurry. The
slurry may be coated on a first side of a foil, such as copper
foil, for example, and dried at an elevated temperature, for
example, about 80.degree. C. to about 100.degree. C. Using the same
procedures, the slurry may be coated on the second surface of the
foil and dried. Subsequently, the coated foil may be compression
molded by a roll press and cut into a predetermined size to prepare
the anode plate 12.
[0018] Coated foils may be directly fed into a drying oven to bake
the electrode material onto the foil. The coated foils may
subsequently be fed into slitting machines to cut the foil into
narrower strips suitable for different sizes of electrodes. As
mentioned above, the foils may also be cut into appropriately
dimensioned strips prior to coating.
[0019] In a cylindrical battery 10 as shown, the stacked layers
(long strips of anode and cathode plates separated by separator
sheets) may be wound on a mandrel and rolled together to form a
spirally wound cylindrical shape. In alternate variants, the
stacked layers may be folded to provide a rectangular shape, or a
plurality of sheets may simply be stacked in alternating layers of
cathode plates 11 and anode plates 12. Prismatic cells are often
used for high capacity battery applications to optimize the space.
These designs use a stacked electrode structure in which the anode
and cathode foils are cut into individual electrode plates which
are stacked alternately and kept apart by the separator. The
separator may be cut to the same size as the electrodes but may
also be applied in a long strip wound in a zigzag fashion between
alternate electrodes in the stack. Prismatic cell designs are
generally considered to provide the optimum use of space for
battery packs.
[0020] To form an electrode group, at least one electrical lead 15
may be attached to the anode plate 12, and at least one electrical
lead 17 may be attached to the cathode plate 11. For cylindrical
cells, since only one continuous cathode and one continuous anode
are used, only two electrode strips are needed. The electrode group
may be inserted into a container, such as a battery can 14 with the
negative lead 15 attached to the bottom of the can, and the
positive lead 17 attached to a sealing lid 16. The sealing lid 16
may be separated from the can 14 by a packing 18. An insulating
plate 19 may also be provided to isolate the edges of the plates
11, 12 from the can 14 and sealing lid 16.
[0021] A non-aqueous electrolyte having lithium ions for
electrochemically bonding with the cathode and anode may be
provided in the battery can 14 to surround the plates 11, 12. The
electrolyte wets the separator and electrodes and is distributed
more or less throughout the layers.
[0022] The non-aqueous electrolyte may be formed by dissolving a
lithium salt in a non-aqueous solvent. The lithium salt supplies
lithium ions to move in the electrolyte upon charging/discharging
of the battery. Some examples of lithium salts may include
LiClO.sub.4, LiCF.sub.3SO.sub.3, LiPF.sub.6, LiBF.sub.4,
LiAsF.sub.6, and similar salts, and combinations thereof. Some
examples of organic solvents may include, carbonates, esters and
ethers including, for example, ethylene carbonate, propylene
carbonate, butylene carbonate, dimethyl carbonate, diethyl
carbonate, methyl ethyl carbonate, diethyl carbonate,
.gamma.-butyrolactone, and similar solvents, and combinations
thereof. Various additives may also be added to the electrolyte
solution, as necessary, for example, with an aim of suppressing
side reactions of the battery and improving the stability. The
additives may include, for example, sulfur type compounds,
phosphorus type compounds, those dissolved in the solvent and those
serving also as the solvent.
[0023] During charging, lithium ions are de-intercalated from the
cathode active material of cathode plate 11 into the non-aqueous
electrolyte, and lithium ions corresponding to the amount of the
de-intercalated lithium ions are intercalated from the non-aqueous
electrolyte to the anode active material of anode plate 12. During
discharging, lithium ions intercalated by charging to the anode
active material are de-intercalated into the non-aqueous
electrolyte and intercalated in the cathode active material.
[0024] The traversing of lithium ions across the electrolytic
materials in a lithium-ion battery, to and from the positive
electrode material, induces disorder in the crystalline structure
of the positive electrode. This disorder induces impurities in the
crystalline structure of the positive electrode, changing the
structure of the crystal, and thus, the function. The induced
structures imposed by charging/discharging cycles of the battery
eventually render the battery useless for its intended purpose.
[0025] The lithium containing cathode material may be recovered
from a partially or fully depleted Li-ion battery, recycled, and
regenerated for use in other batteries via a general process as set
forth in FIG. 2A. The method may generally include recovering
lithium metal oxide from lithium-ion batteries 50, converting at
least a portion of the lithium metal oxide to lithium halide and a
metal oxide 55, reducing the lithium halide and the metal oxide to
respective nanoparticles 60, and combining the lithium
nanoparticles with the metal nanoparticles in the presence of
oxygen to produce regenerated lithium metal oxide 65.
[0026] FIG. 2B provides a more detailed depiction for regenerating
lithium metal oxides. As depicted in FIG. 2B, the method may
include dis-assembling 101 partially or fully depleted Li-ion
batteries 100 into various components that may include the case
102, foils 104, cathode material 106, and other components 108,
110. For example, the cathode material 106 may be scraped off of
the cathode foil 104 with a scraper. For larger scale production,
solvents, or other methods may be applied to remove the cathode
materials 106 from the foils 104. In an embodiment, and as
discussed above, the lithium metal oxide cathode material may be
LiCoO.sub.2.
[0027] After separation, the process may include drying, sieving,
and powdering of the lithium metal oxide cathode material 106 into
particles having a size of less than or equal to about 200 .mu.m.
Smaller particles sizes are desired to provide the greatest
reactive surface area for processing. Heating 112 of the lithium
metal oxide cathode material 106 may be done under oxidizing
conditions to oxidize the lithium metal oxide cathode material
resulting in a mixture 114 of lithium oxide and metal oxide. In an
embodiment, the heating may be done at a temperature of about
200.degree. C. to about 1000.degree. C. for a period of time of
about 10 minutes to about 2 hours in the presence of water or water
and a binder solvent. Any binders in the cathode material 106 may
vaporize during the heating 112.
[0028] For an embodiment with LiCoO.sub.2 materials, a general
reaction may be depicted as follows:
2LiCoO.sub.2=Li.sub.2O+Co.sub.2O.sub.3.
The resultant oxide material may be finely powdered and may contain
a mixture of lithium oxides (Li.sub.2O) and metal oxides (CoO,
Co.sub.2O.sub.3 and Co.sub.3O.sub.4).
[0029] Hydration 116 of the oxides in the mixture 114 may be done
by placing the mixture 114 in distilled water with stirring for
about 24 hours at ambient temperature to decompose the Li.sub.2O to
lithium hydroxide (LiOH), thereby resulting in a mixture 118 of
metal oxides and lithium hydroxide. Alternatively, the mixture 114
may be heated with stirring to about 80.degree. for about 10 to
about 30 minutes, and then left with stirring for an additional 2-3
hours under ambient conditions. For an embodiment with LiCoO.sub.2
materials, a general reaction may be depicted as follows:
Li.sub.2O+H.sub.2O+Co.sub.2O.sub.3.fwdarw.2LiOH+Co.sub.2O.sub.3.
[0030] The LiOH is soluble in water, and the metal oxides may
precipitate out. Separation 120 may be done to separate the lithium
from the metal. The separation 120 may include decanting of the
LiOH solution 122, and/or filtering the metal oxides 124 from the
solution. The metal oxides 124 may be dried, powdered and washed.
The extracted metal oxides 124 may also contain lithium hydroxide,
carbon, and some polymer binder impurities, but these components
seem to have minimal, if any, adverse effect on the regeneration
process.
[0031] The process may include halogenation 126 of the LiOH 122 to
produce lithium halide 128. The halogenation 126 may include adding
an appropriate concentrated hydrohalic acid to the solution.
Hydrohalic acids may include, hydrochloric (HCl), hydrofluoric
(HF), hydrobromic (HBr) and hydroiodic (HI). Isolation of the
lithium halide 128 may be done by evaporating the aqueous solution.
For an embodiment, a general reaction may be depicted as
follows:
LiOH+HCl.fwdarw.LiCl+H.sub.2O.
[0032] Regeneration of lithium metal oxide 140 may be done at
ambient temperature and pressure by combining the metal oxides 124
and the lithium halide 128 together in the presence of a metal
halide 130 and a reducing agent 132. This reaction may be carried
out in an aqueous solution such as, for example, a 2:1 solution of
ethanol and water. Examples of reducing agents may include, sodium
borohydride (NaBH.sub.4), hydrogen gas, carbon monoxide, lithium
borohydride (LiBH.sub.4), hydroquinone, hydrazine hydrate, calcium
hydride, sodium hydride, N-dimethylformamide, sodium citrate, and
combinations thereof. The resultant sequential reaction steps 134
may produce a mixture 136 of individual nanoparticles of lithium
and individual nanoparticles of metal in a nanoparticle mixture
136. The nanoparticles of lithium and nanoparticles of metal may
combine to form lithium/metal hybrid nanoparticles 138. The
lithium/metal hybrid nanoparticles 138 are very unstable and may
immediately combine with free oxygen in the mixture to form lithium
metal oxide 140.
[0033] For an embodiment with lithium chloride and cobalt oxides, a
general reaction sequence may be depicted as follows
(NP=nanoparticles):
LiCl+Co (II, III) oxide+CoCl.sub.2.6H.sub.2O+2NaBH.sub.4.fwdarw.Li
NP+Co NP+2NaCl+H.sub.3BO.sub.3+6H.sub.2O+H.sub.2
Li NP+Co NP+H.sub.2.fwdarw.Li/Co NP (unstable)
which, in the presence of oxygen in the solution, may then proceed
as follows:
Li/Co
NP+O.sub.2.fwdarw.LiCoO.sub.2+2NaCl+H.sub.3BO.sub.3+6H.sub.2O.
This reaction scheme may be expected since:
CoCl.sub.2.6H.sub.2O+2NaBH.sub.4.fwdarw.Co
NP+2NaCl+H.sub.3BO.sub.3+6H.sub.2O+H.sub.2; and
LiCl+NaBH.sub.4.fwdarw.Li
NP+NaCl+H.sub.3BO.sub.3+6H.sub.2O+H.sub.2.
This reaction sequence may be summarized by the following:
LiCl+cobalt
oxide+CoCl.sub.2.6H.sub.2O+NaBH.sub.4.fwdarw.LiCoO.sub.2+NaCl+H.sub.3BO.s-
ub.3+H.sub.2O+H.sub.2,
wherein the cobalt oxide may be cobalt(II) oxide (cobaltous
oxide--CoO), cobalt(III) oxide (cobaltic oxide--CO.sub.2O.sub.3),
cobalt(II,III) oxide--CO.sub.3O.sub.4).
[0034] In embodiments in which a high molarity reducing agent, such
as NaBH.sub.4, or excess of metal halide, such as
CoCl.sub.2.6H.sub.2O is used or present, cobalt boride (Co.sub.2B)
may be produced. If Co.sub.2B is in minute quantities, it may be
removed from the surface of the material. To avoid Co.sub.2B
formation, some excess lithium halide (such as lithium chloride)
may be added. This may be due to higher electro positivity of
lithium than boron, thus making lithium more reactive. However, too
much LiCl and very low molarity of NaBH.sub.4 may result in the
production of unstable LiCoO.sub.2 (precipitated), which may
spontaneously convert to CoCl.sub.2 (soluble) within a few minutes
due to presence of excess chlorine atoms in solution. Addition of
more NaBH.sub.4 may again convert CoCl.sub.2 back to
LiCoO.sub.2.
[0035] Impurities like LiOH, carbon, and polymer binder in the
extracted cobalt oxide material (from spent batteries) does not
seem to have any adverse effect on the synthesis procedure and
electrical performance of the regenerated material. Any residual
LiOH may also be converted to LiCl, when LiCl (LiOH+HCl) is added
to the solution.
[0036] In an embodiment, a method for regenerating a cathode
material from a partially or fully depleted Li-ion battery, may
include recovering lithium metal oxide from the Li-ion battery,
converting at least a portion of the lithium metal oxide to lithium
halide and a metal oxide, reducing the lithium halide and the metal
oxide to respective nanoparticles, and combining the lithium
nanoparticles with the metal nanoparticles in the presence of
oxygen to produce regenerated lithium metal oxide.
[0037] In an embodiment, after recovering the lithium metal oxide,
the lithium metal oxide may be powdered to particles having an
average size of equal to or less than about 200 micrometers. As
mentioned above, the lithium metal oxide may be any lithium metal
oxide represented by the formula Li.sub.xMO.sub.y, where M is one
or more transition metals each having a stable formal oxidation
state of +2 or +3, and (x+3-z)/2.ltoreq.y.ltoreq.(x+3+z)/2, where z
is 0, 1 or 2. In an embodiment, the value of x may be 1, and M may
be at least one of Mn, Co or Ni.
[0038] In an embodiment, the lithium nanoparticles may be combined
with the metal nanoparticles in the presence of oxygen at ambient
temperature and/or ambient pressure. The step of converting of at
least a portion of the lithium metal oxide to lithium halide and
the metal oxide may include oxidizing the lithium metal oxide to
lithium oxide and the metal oxide, hydrating the lithium oxide to
lithium hydroxide, and halogenating the lithium hydroxide to the
lithium halide. Oxidation of the lithium metal oxide may include
heating the lithium metal oxide under oxidizing conditions at a
temperature and for a period of time sufficient for oxidizing the
lithium metal oxide, and halogenation may include contacting the
lithium hydroxide with a hydrohalic acid. The hydrohalic acid may
be hydrochloric acid, hydrofluoric acid, hydrobromic acid,
hydroiodic acid, or any combination thereof.
[0039] The step of reducing the lithium halide and the metal oxide
to respective nanoparticles may include reducing the lithium halide
and metal oxide in the presence of metal halide to produce the
nanoparticles of lithium and the nanoparticles of metal. This
reduction may be performed in the presence of a reducing agent at a
temperature and for a period of time sufficient for reducing the
lithium halide the metal oxide and the metal halide. The reduction
may include contacting the lithium halide, metal halide and metal
oxide with hydrogen gas to reduce the lithium halide to lithium
nanoparticles and reduce the metal halide and the metal oxide to
metal nanoparticles, and the contacting with hydrogen gas may be
performed at a pressure less than ambient atmospheric pressure.
[0040] In the above-discussed procedural steps, the metal of the
metal oxide may be the same as the metal of the metal halide, and
in an embodiment, the metal of the metal oxide and the metal halide
may be Co, Mn or Ni.
[0041] In an embodiment wherein the lithium metal halide is
LiCoO.sub.2, a method for regenerating a cathode material from a
partially or fully depleted Li-ion battery, may include recovering
LiCoO.sub.2 from the Li-ion battery. After recovery, at least a
portion of the LiCoO.sub.2 may be converted to lithium halide, CoO
and Co.sub.3O.sub.4. In a subsequent reduction step, the lithium
halide may be reduced to nanoparticle of lithium, the CoO and
Co.sub.3O.sub.4 may be reduced to nanoparticles of cobalt, and, in
the presence of oxygen, the lithium nanoparticles may combine with
the cobalt nanoparticles to produce regenerated LiCoO.sub.2.
[0042] In an embodiment, the reduction step may include reducing
the lithium halide, CoO, and Co.sub.3O.sub.4 in the presence of
cobalt halide to produce the nanoparticle of lithium and the
nanoparticles of cobalt. The reduction may be performed in the
presence of a reducing agent. Examples of reducing agents are
discussed above. In an embodiment wherein the lithium halide may be
lithium chloride, the reduction may include reducing the LiCl, CoO
and Co.sub.3O.sub.4 in the presence of CoCl.sub.2.6H.sub.2O and
NaBH.sub.4.
[0043] The regenerated lithium metal oxide from the above
procedures may be used for producing a Li-ion battery. In a manner
as discussed above, with reference to FIG. 1, a metal foil may be
coated with the regenerated material, and the coated metal foil may
be layered with a separator sheet and an anode sheet to produce a
stacked electrode structure. The stacked electrode structure may be
contacted with an electrolyte solution to produce a Li-ion
battery.
[0044] The particle size of the regenerated lithium metal oxide may
be reduced to an average size equal to or less than about 200 .mu.m
to achieve the maximum effective surface area of the electrodes.
The reduced particle size lithium metal oxide may be mixed with a
conducting material, such as carbon black or another conducting
material as described above, and a binder, such as PEG or another
binder as discussed above, to form a lithium metal oxide paste for
coating the foil.
[0045] In an embodiment, the paste may be applied to both sides of
the foil, either one side at a time with a corresponding drying to
deposit the lithium metal oxide paste onto the foil, or essentially
simultaneously with a single drying step.
[0046] In view of the above procedural steps, a general method for
producing lithium metal oxides may include forming a mixture of at
least one lithium halide and at least one metal oxide, reducing the
lithium halide and the metal oxide to respective nanoparticles, and
combining the lithium nanoparticles with the metal nanoparticles in
the presence of oxygen to produce regenerated lithium metal
oxide.
[0047] The reduction of the lithium halide and metal oxide to
respective nanoparticles may include reducing the lithium halide
and metal oxide in the presence of at least one metal halide to
produce the nanoparticles of lithium and the nanoparticles of
metal. This reduction may include contacting the lithium halide,
the metal halide and the metal oxide with a reducing agent at a
temperature and for a period of time sufficient for reducing the
lithium halide to lithium nanoparticles and reducing the metal
halide and the metal oxide to metal nanoparticles. Examples of
reducing agents are provided herein.
[0048] In an embodiment, the metal of the metal oxide may be the
same as the metal of the metal halide, and may be at least one of
Co, Mn or Ni. As set forth herein, the at least one lithium halide
and the at least one metal oxide may be obtained from a partially
or fully depleted Li-ion battery by a method that includes
recovering lithium metal oxide from the Li-ion battery, and
converting the lithium metal oxide to lithium halide and a metal
oxide.
EXAMPLE 1
Recovery of Cathode Materials from Li-Ion Batteries
[0049] Li-ion batteries were dis-assembled and the various
different components were separated. The foils having the
LiCoO.sub.2 pasted thereon were scraped with a non-metallic scraper
to remove the LiCoO.sub.2. The LiCoO.sub.2 was dried, sieved and
ground to a fine powder of particles having an average size of less
than or equal to about 200 .mu.m.
[0050] The LiCoO.sub.2 was moderately heated to a temperature of
about 400.degree. C. for about 1 hour at ambient pressure and under
oxidizing conditions to vaporize any binders and oxidize the
LiCoO.sub.2 to lithium oxide (Li.sub.2O) and cobalt oxides (CoO,
Co.sub.2O.sub.3 and Co.sub.3O.sub.4). This mixture of oxides was
then hydrated by placing the mixture in distilled water with
stirring for about 24 hours. The hydration decomposed the Li.sub.2O
to LiOH that is soluble in water, while the cobalt oxides
precipitated out. The LiOH solution was decanted. The cobalt oxides
were dried, powdered and washed four times. The LiOH in solution
was converted to LiCl by adding concentrated hydrochloric acid to
the solution. The LiCl was then isolated by evaporating the aqueous
solution.
EXAMPLE 2
Producing Lithium Metal Oxides
[0051] Cobalt(II & III) oxides (CoO, Co.sub.3O.sub.4) and LiCl,
such as those recovered in Example 1, were used to produce
LiCoO.sub.2. A 2:1 ethanol water solution was prepared, and 2.2 g
of 1M CoCl.sub.2.6H.sub.2O was dissolved in the solution, producing
a pink colored solution. To this pink solution was added 11 g of
powdered cobalt oxide, and the color changed to blue-violet to
violet black. While stirring, 6.12 ml of 10M LiCl were added, and
the color changed to dark green. This resultant solution had
approximately a 1:1:2 ratio of cobalt
oxides:CoCl.sub.2.6H.sub.2O:LiCl so that the lithium to cobalt
ratio was about 1:1. About 25 ml of the reducing agent 1M
NaBH.sub.4 was added drop-wise with vigorous stirring, wherein the
color changed to grey, then dark grey, and finally black,
indicative that LiCoO.sub.2 had been synthesized.
[0052] When NaBH.sub.4 was added drop wise to reduce
CoCl.sub.2.6H.sub.2O and cobalt oxide to produce cobalt
nanoparticles, LiCl was also simultaneously reduced to lithium
nanoparticles. Immediately after the formation of the Co and Li
nanoparticles, the Co and Li nanoparticles combined to form lithium
and cobalt hybrid nanoparticles (LiCo). Since lithium and cobalt
hybrid nanoparticles are extremely unstable, the nanoparticles were
immediately oxidized by dissolved oxygen in the aqueous medium to
produce LiCoO.sub.2.
[0053] The synthesized LiCoO.sub.2 material was allowed to
precipitate, and the aqueous solution, containing dissolved NaCl
and H.sub.3BO.sub.3 by-products, was separated by decantation. The
regenerated LiCoO.sub.2 was dried in a dry air oven for about 48
hours at about 60.degree. C. FIGS. 3A and 3B respectively show
High-Resolution X-Ray Diffraction (XRD) scans of regenerated
LiCoO.sub.2 in comparison with LiCoO.sub.2 produced by other
methods. The generated scan of FIG. 3A was compared with the XRD
database using PcPdfWin software, that matched the scan in FIG. 3A
with that of FIG. 3B, showing a significant match. The higher peaks
in FIG. 3A indicate that the LiCoO.sub.2 produced by the described
process may have mild magnetic properties, which is possible since
the entire synthesis is performed in ambient conditions.
[0054] FIGS. 4A and 4B respectively show Fourier-Transform
Infra-Red (FTIR) scans of the regenerated LiCoO.sub.2 in comparison
with LiCoO.sub.2 produced by other methods. The `major` similar
peaks may be seen in both scans. Any variations between the scans
of FIGS. 4A and 4B may possibly be due to variations in the
proportion of lithium, cobalt and oxygen that may result from the
synthesis time or the time of addition of the reducing agent.
[0055] FIGS. 5A-5D show voltammetry scans of the regenerated
LiCoO.sub.2, essentially indicating its usefulness for rechargeable
batteries. Cyclic voltammograms (CV) show the oxidation and
reduction peaks of a material to provide an indicator of the
electrochemical properties of the material. Since LiCoO.sub.2 is
poorly soluble in DMSO, the oxidation or reduction peaks in DMSO
were only obtainable in separate scans (FIGS. 5A and 5B). With
acetonitrile as the solvent, full loop oxidation and reduction
scans of LiCoO.sub.2 were attained (FIGS. 5C and 5D). The shape of
CV curves may be used to deduce the electrochemical processes
involved in the charging and discharging a storage device, such as
the LiCoO.sub.2 materials. The current initially increases when
charging from zero potential, and then decreases upon further
increase in the electric potential. Thus, a peak is observed in the
CV. The reasons for the peak in CV curves may be attributed to
several factors, including: the "electrolyte starvation" due to
limited amount of ions at low concentrations; redox reactions at
the electrode surface as well as the "difference of diffusion
capability between solvated anions and cations in the electrolyte";
and the "available active surface becoming fully saturated with
ions" before reaching the maximum potential (this current
decreases, even with increasing voltage).
EXAMPLE 3
Use of Regenerated LiCoO.sub.2 in a Lithium-Ion Battery
[0056] The dried, regenerated LiCoO.sub.2 of Example 2 was mixed
with PEG binder and carbon black in NMP solvent to produce a slurry
for the cathode material for a Li-ion battery. The `cathode` slurry
was coated on a first side of an aluminum foil having a thickness
of about 20 .mu.m, and dried at a temperature from about 80.degree.
C. to 100.degree. C. The same procedure was then repeated on the
second side of the foil. The coated foil was compression molded by
a roll press, and cut into an elongated strip to form a cathode
plate.
[0057] An anode plate was prepared using a similar procedure.
Carbon black was mixed with PEG binder in PVDF solvent to form a
slurry for the anode material for a Li-ion battery. The `anode`
slurry was coated on a first side of a copper foil having a
thickness of about 20 .mu.m, and dried at a temperature from about
80.degree. C. to 100.degree. C. The same procedure was then
repeated on the second side of the foil. The coated foil was
compression molded by a roll press, and cut into an elongated strip
to form an anode plate.
[0058] A finely porous polyethylene (PE) film having a thickness of
about 25 .mu.m was used as a separator sheet. Cathode and anode
strips were attached to the respective plates. The anode plate was
laid flat and covered by a first separator sheet. The cathode plate
was placed on the first separator sheet and a second separator
sheet was placed over the cathode plate. The assembled sheets were
rolled from one end to produce a cylindrical cell.
[0059] The cylindrical cell was placed in a sealable container,
leaving the cathode and anode protruding therefrom, and the
container was then filled with an electrolyte solution of
LiPF.sub.6, in ethylene carbonate (EC). The container was then
sealed to provide a Li-ion rechargeable battery.
EXAMPLE 4
A Li-Ion Battery with Regenerated LiCoO.sub.2 (1:1)
[0060] LiCoO.sub.2 (1:1) was synthesized from cobalt oxide (spent
batteries): cobalt chloride in 1:1 ratio. A 5 cm diameter plastic,
lidded container was used to make a rechargeable battery with a
slurry of regenerated dried LiCoO.sub.2 (1:1), carbon powder and
polyethylene glycol as cathode. A separator was obtained from a
Li-ion mobile battery after dismantling of the battery and careful
removal of the separator. The separator was cut to accurate size
and shape to fit in the plastic container. The separator was placed
over the regenerated LiCoO.sub.2 and carbon cathode material.
Activated carbon and polyethylene glycol was used as the anode,
which was fitted in the lid of the box. The lid was placed on the
box with the anode then positioned above the separator already
fitted above the cathode in the box bottom. Electrolyte materials
were added and the lid was closed. The battery was charged and
discharged for more than 100 times during a period of 15 days. The
battery showed up to about 3.9 volt open circuit discharge, whereas
a continuous discharge of about 2.4-2.8 volts was observed.
EXAMPLE 5
A Li-Ion Battery with Regenerated LiCoO.sub.2 (5:1)
[0061] LiCoO.sub.2 (5:1) was synthesized from cobalt oxide (spent
batteries): cobalt chloride in 5:1 ratio. A 5 cm diameter plastic,
lidded container was used to make rechargeable battery with a
slurry of regenerated dried LiCoO.sub.2 (5:1), carbon powder and
polyethylene glycol as cathode. A separator was obtained from a
Li-ion mobile battery after dismantling of the battery and careful
removal of the separator. The separator was cut to accurate size
and shape to fit in the plastic weight box. The separator was
placed over the regenerated LiCoO.sub.2 and carbon cathode
material. Activated carbon and polyethylene glycol was used as the
anode, which was fitted in the lid of the box. The lid was placed
on the box with the anode then positioned above the separator
already fitted above the cathode in the box bottom. Electrolyte
materials were added and the lid was closed. The battery was
charged (about 2-4 hours) and provided up to about 3.7 volt open
circuit discharge, whereas a continuous discharge of about 2.4-2.8
volts was observed.
EXAMPLE 6
A Li-Ion Pouch Battery with Regenerated LiCoO.sub.2 (5:1)
[0062] A pouch cell (about 4 cm.times.4 cm) was made using
regenerated LiCoO.sub.2 mixed with carbon and polyethylene glycol
as cathode material. Only carbon powder mixed with polyethylene
glycol was used as the anode. Two long strips of aluminum foil
(about 30 cm.times.8 cm) were cut, and cathode and anode slurries
were pasted on both sides of the foils. Both of the cathode and
anode material pasted aluminum foils were dried on an electric
heater. A separator membrane was obtained from a Li-ion mobile
battery. Two separators were placed carefully on both sides of the
cathode strip to prevent direct contact between the anode and
cathode, and the assembly was folded together. Two connectors were
inserted, one to each of the cathode part and the anode part of the
cell. The cell was covered tightly by cello tape. This rechargeable
pouch cell was charged by a mobile charger, and discharged up to
about 2.9 volts.
[0063] This disclosure is not limited to the particular systems,
devices and methods described, as these may vary. The terminology
used in the description is for the purpose of describing the
particular versions or embodiments only, and is not intended to
limit the scope.
[0064] In the above detailed description, reference is made to the
accompanying drawings, which form a part hereof. In the drawings,
similar symbols typically identify similar components, unless
context dictates otherwise. The illustrative embodiments described
in the detailed description, drawings, and claims are not meant to
be limiting. Other embodiments may be used, and other changes may
be made, without departing from the spirit or scope of the subject
matter presented herein. It will be readily understood that the
aspects of the present disclosure, as generally described herein,
and illustrated in the Figures, can be arranged, substituted,
combined, separated, and designed in a wide variety of different
configurations, all of which are explicitly contemplated
herein.
[0065] The present disclosure is not to be limited in terms of the
particular embodiments described in this application, which are
intended as illustrations of various aspects. Many modifications
and variations can be made without departing from its spirit and
scope, as will be apparent to those skilled in the art.
Functionally equivalent methods and apparatuses within the scope of
the disclosure, in addition to those enumerated herein, will be
apparent to those skilled in the art from the foregoing
descriptions. Such modifications and variations are intended to
fall within the scope of the appended claims. The present
disclosure is to be limited only by the terms of the appended
claims, along with the full scope of equivalents to which such
claims are entitled. It is to be understood that this disclosure is
not limited to particular methods, reagents, compounds,
compositions or biological systems, which can, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting.
[0066] As used in this document, the singular forms "a," "an," and
"the" include plural references unless the context clearly dictates
otherwise. Unless defined otherwise, all technical and scientific
terms used herein have the same meanings as commonly understood by
one of ordinary skill in the art. Nothing in this disclosure is to
be construed as an admission that the embodiments described in this
disclosure are not entitled to antedate such disclosure by virtue
of prior invention. As used in this document, the term "comprising"
means "including, but not limited to."
[0067] While various compositions, methods, and devices are
described in terms of "comprising" various components or steps
(interpreted as meaning "including, but not limited to"), the
compositions, methods, and devices can also "consist essentially
of" or "consist of" the various components and steps, and such
terminology should be interpreted as defining essentially
closed-member groups.
[0068] With respect to the use of substantially any plural and/or
singular terms herein, those having skill in the art can translate
from the plural to the singular and/or from the singular to the
plural as is appropriate to the context and/or application. The
various singular/plural permutations may be expressly set forth
herein for sake of clarity.
[0069] It will be understood by those within the art that, in
general, terms used herein, and especially in the appended claims
(e.g., bodies of the appended claims) are generally intended as
"open" terms (e.g., the term "including" should be interpreted as
"including but not limited to," the term "having" should be
interpreted as "having at least," the term "includes" should be
interpreted as "includes but is not limited to," etc.). It will be
further understood by those within the art that if a specific
number of an introduced claim recitation is intended, such an
intent will be explicitly recited in the claim, and in the absence
of such recitation, no such intent is present. For example, as an
aid to understanding, the following appended claims may contain
usage of the introductory phrases "at least one" and "one or more"
to introduce claim recitations. However, the use of such phrases
should not be construed to imply that the introduction of a claim
recitation by the indefinite articles "a" or "an" limits any
particular claim containing such introduced claim recitation to
embodiments containing only one such recitation, even when the same
claim includes the introductory phrases "one or more" or "at least
one" and indefinite articles such as "a" or "an" (e.g., "a" and/or
"an" should be interpreted to mean "at least one" or "one or
more"); the same holds true for the use of definite articles used
to introduce claim recitations. In addition, even if a specific
number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should
be interpreted to mean at least the recited number (e.g., the bare
recitation of "two recitations," without other modifiers, means at
least two recitations, or two or more recitations). Furthermore, in
those instances where a convention analogous to "at least one of A,
B, and C, etc." is used, in general, such a construction is
intended in the sense one having skill in the art would understand
the convention (e.g., "a system having at least one of A, B, and C"
would include but not be limited to systems that have A alone, B
alone, C alone, A and B together, A and C together, B and C
together, and/or A, B, and C together, etc.). In those instances
where a convention analogous to "at least one of A, B, or C, etc."
is used, in general, such a construction is intended in the sense
one having skill in the art would understand the convention (e.g.,
"a system having at least one of A, B, or C" would include but not
be limited to systems that have A alone, B alone, C alone, A and B
together, A and C together, B and C together, and/or A, B, and C
together, etc.). It will be further understood by those within the
art that virtually any disjunctive word and/or phrase presenting
two or more alternative terms, whether in the description, claims,
or drawings, should be understood to contemplate the possibilities
of including one of the terms, either of the terms, or both terms.
For example, the phrase "A or B" will be understood to include the
possibilities of "A" or "B" or "A and B."
[0070] In addition, where features or aspects of the disclosure are
described in terms of Markush groups, those skilled in the art will
recognize that the disclosure is also thereby described in terms of
any individual member or subgroup of members of the Markush
group.
[0071] As will be understood by one skilled in the art, for any and
all purposes, such as in terms of providing a written description,
all ranges disclosed herein also encompass any and all possible
subranges and combinations of subranges thereof. Any listed range
can be easily recognized as sufficiently describing and enabling
the same range being broken down into at least equal halves,
thirds, quarters, fifths, tenths, etc. As a non-limiting example,
each range discussed herein can be readily broken down into a lower
third, middle third and upper third, etc. As will also be
understood by one skilled in the art all language such as "up to,"
"at least," and the like include the number recited and refer to
ranges which can be subsequently broken down into subranges as
discussed above. Finally, as will be understood by one skilled in
the art, a range includes each individual member. Thus, for
example, a group having 1-3 cells refers to groups having 1, 2, or
3 cells. Similarly, a group having 1-5 cells refers to groups
having 1, 2, 3, 4, or 5 cells, and so forth.
[0072] Various of the above-disclosed and other features and
functions, or alternatives thereof, may be combined into many other
different systems or applications. Various presently unforeseen or
unanticipated alternatives, modifications, variations or
improvements therein may be subsequently made by those skilled in
the art, each of which is also intended to be encompassed by the
disclosed embodiments.
* * * * *