Ammonia Reduction System for the Diversity of Cathode Processing of Li-Ion Batteries

This study breaks the traditional notion of spent cathode processing and develops a specific approach using the ammonia reduction system to take advantage of the residual value of spent Li-ion batteries (LIBs), optionally for the purpose of down-cycle or up-cycle processing. For cathode down-cycling as metal resources, >97% lithium with nearly 100% selectivity is recycled as lithium salts in one step, while other transition metals including nickel, cobalt, and manganese are recovered as metals or metal oxides. For cathode up-cycling as value-added materials, the cathode from LIBs is directly processed to synthesize the core–shell structure composites as Li-doped Co@g-C3N4 materials whose degradation rate is about 11 times higher than that of fresh g-C3N4. This LIB-specific technology can realize the diversity of LIB processing which can be called as "kill two birds with one stone". From the down-cycling perspective, metal resources can be effectively recovered to meet the demand of explosive increasing LIB production. Besides, the up-cycling cathode as the enhanced photocatalyst provides technical storage and support for the future development of spent LIB processing diversity.