Graphite recycling from li-ion batteries
OwnerYan Wang, Zeyi Yao +1inventors
InventorsYan Wang, Zeyi Yao, Xiaotu MA
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Abstract
A purification process for recycled graphite for use as anode material in Li-ion batteries includes a sequence of leaching and heat treatment followed by washing with deionized (DI) water and an acid wash. A graphite source results from a suitable process such as acid leaching of black mass from a battery recycling stream, where the leach removes a substantial portion of metal salts used for cathode materials. Impurities, most notably aluminum oxide and residual cathode materials, are often present in trace amounts in the graphite source. A sequence of heating (sintering) and pH adjusted washing further purifies the graphite into a modified, recycled graphite exceeding 99.5% purity for use in a recycled battery.
Claims14
A method of recycling graphite from a Li-ion battery, comprising:
- receiving an initial recycled graphite from recycling stream of dismantled Li-ion batteries including anode material;
- washing the anode material in an acidic wash solution for removing residual charge material metals;
- sintering the anode material with NaOH for forming a sintered graphite from the anode material;
- combining a tetrahydrofuran (THF) solution with the sintered graphite to form a reduced graphite;
- and
- washing the reduced graphite in a final wash solution to attain a pH between 6 and 8 for forming a modified recycled graphite configured for use as anode material in a recycled battery.
A method for recycling anode material from a Li-Ion battery, comprising:
- leaching charge material metals from a comingled recycling stream of crushed Li-ion batteries to form acid leached recycled graphite (ARG);
- sintering the ARG with NaOH and washing with deionized water (DI) and additional NaOH to form sintered acid leached recycled graphite (SARG), thereby removing residual aluminum oxide;
- synthesizing reduced recycled graphite by combining the SARG with lithium aluminum hydride (LiAlH4) and an HCl solution to generate reduced recycled graphite.
A system for receiving a recycling stream of NMC batteries and recycling graphite for use as recycled anode charge material, comprising:
- a receptacle for receiving an initial recycled graphite from recycling stream of dismantled Li-ion batteries including anode material;
- a containment washing the anode material in an acidic wash solution for removing residual charge material metals;
- a heat source for sintering the anode material with NaOH for forming a sintered graphite from the anode material;
- a reactor vessel for combining a tetrahydrofuran (THF) solution with the sintered graphite to form a reduced graphite;
- and
- a rinse process washing the reduced graphite in a final wash solution to attain a pH between 6 and 8 for forming a modified recycled graphite configured for use as anode material in a recycled battery.
Dependencies are inferred from the claim text.