Unravelling Li-ion Storage Capability of Cobalt Oxide Anode Recovered from Spent LiCoO2 Cathode via Carbothermal Reduction

Abstract

With the advent of globalization, the upsurge of lithium-ion battery (LIB) production and generation of spent batteries impose a severe threat as hazardous e-waste and resource sustainability of crucial elements like cobalt and lithium. Herein, we propose one-step regeneration of cobalt oxide (RCO) from cycled LiCoO2 (LCO)-type cathode via carbon anode-assisted reduction. The inherent structural changes resulting in high irreversibility are minimized in conversion-type mixed-phase recycled cobalt oxide anode due to less Li-ion consumption and stable SEI formation during initial cycles. Replacement of conventional Cu-foil current collector with carbon-fiber (CF) based freestanding electrode further enhances the Li-ion storage capacity with overall active material utilization, accommodating volume changes in the internal void spaces and providing mechanical stability. Electrochemistry reveals that RCO@CF and RCO@Cu deliver an initial discharge capacity of 3800 mAh g−1 and 1432 mAh g−1 at 30 mAg−1 with 77% and 64% coulombic efficiency that becomes ∼97% in the following cycles. Besides, RCO@CF shows an average discharge capacity of 730 mAh g−1 at 300 mA g−1 over 300 cycles, which is ∼2.7 times that of recycled graphite anode (270 mAh g−1). The sustainable recycling strategy described herein rejuvenates the cycled LCO-type cathode as an appealing anode material for LIBs.