Worcester Polytechnic Institute

Ascend Elements, Inc.

Eric Gratz

Yan Wang

Zhangfeng Zheng

Joseph Heelan

Kee-Chan Kim

Qina Sa

Xiaotu Ma

Jinzhao Fu

Panawan Vanaphuti

A method for recycling anode materials from a comingled recycling stream derived from exhausted Li ion batteries includes receiving a precipitate quantity remaining from a cathode recycling stream. This precipitate is almost exclusively graphite used for the anode material in the recycled batteries. The precipitate results from an acid leach of charge material from the lithium battery recycling stream. A strong acid is added to the precipitate for removal of residual cathode and separator materials and the mixture heated. The strong acid removes residual aluminum oxide from the separator by transformation to aluminum sulfate. Washing the acid treated precipitate removes water soluble contaminants, such as the aluminum sulfate reacted from the aluminum oxide and sulfuric acid, to generate substantially pure graphite. Any residual material remaining from the cathode recycling phase is also removed.

Graphite recovery in recycled batteries

Cathode material from exhausted lithium ion batteries are dissolved in a solution for extracting the useful elements Co (cobalt), Ni (nickel), Al (Aluminum) and Mn (manganese) to produce active cathode materials for new batteries. The solution includes compounds of desirable materials such as cobalt, nickel, aluminum and manganese dissolved as compounds from the exhausted cathode material of spent cells. Depending on a desired proportion, or ratio, of the desired materials, raw materials are added to the solution to achieve the desired ratio of the commingled compounds for the recycled cathode material for new cells. The desired materials precipitate out of solution without extensive heating or separation of the desired materials into individual compounds or elements. The resulting active cathode material has the predetermined ratio for use in new cells, and avoids high heat typically required to separate the useful elements because the desired materials remain commingled in solution.

Charge material for recycled lithium-ion batteries

The inventions described herein provide methods and systems for recycling lithium iron phosphate batteries, including: adding an oxidizing agent to a recycling stream of lithium iron phosphate (LiFePO) batteries to form a leach solution; filtering the leach solution to remove a residue and obtain a lithium rich solution; modifying pH of the lithium rich solution for filtering impurities and obtaining a purified Li solution; and adding a precipitant to the purified Li solution thereby precipitating a lithium compound.

Lithium iron phosphate (LFP) battery recycling

A battery recycling process recovers lithium from nickel-rich cathode material in a recycling stream of end-of-life batteries. A dilute acid leach of a high nickel content cathode material contains a mixture of sulfuric acid based on a molar quantity of lithium in the cathode material. The highly selective leach generates a lithium rich solution with a small amount of nickel removable by nanofiltration to achieve a highly efficient recovery of the lithium contained in the recycling stream. A quantity of the leach acid based on the lithium content and a quantity of water based on a total black mass of the recycling stream results in a highly selective, near pure lithium leach when the recycling stream results from high nickel NMC batteries such as 811.

Nickel-rich battery recycling

A recycling and synthesis of charge material for secondary batteries generates single-crystal charge materials for producing batteries with greater charge cycle longevity. Charge material particles undergo a heating for fusing or enhancing grain boundaries between polycrystalline particles. The resulting, more well-defined grain boundaries are easily etched by a relatively weak mineral acid solution. The acid solution removes material at the grain boundaries to separate secondary particles into primary particles along the grain boundaries. The resulting single crystal (monocrystalline) charge material particles are washed and filtered, and typically re-sintered to accommodate any needed lithium (lithium carbonate), and result in a charge material with larger surface area, higher lithium diffusivity and lower cation ordering.

Growing community of inventors

Worcester, MA, United States of America

Eric Gratz