Cobalt and lithium recovery from spent LiCoO2 using a free-standing potassium zinc hexacyanoferrate/carbon cloth composite electrode

Rapid rejuvenation and extensive utilization of mobile electronic devices lead to the excessive accumulation of waste lithium-ion batteries (LIBs), specifically spent LiCoO2 cathode materials. Considering the shortage of metal resources and the surging price of raw materials in the battery industry, an efficient strategy for selectively extracting valuable metals from spent LiCoO2 is urgently required. Herein, nanocube-like potassium zinc hexacyanoferrate (denoted as KZHCF) was successfully fabricated on a carbon cloth (CC) substrate for selective Co2+ adsorption from a spent LiCoO2 cathode via the combination of simple electrodeposition and hydrothermal treatment. Under optimal operational conditions, 98.6% of Co2+ was effectively extracted within 120 min at a constant potential of −0.4 V (vs. Ag/AgCl) with the CC/KZHCF composite as the working electrode, accompanied with a Co2+ electrosorption capacity of 130.9 mg g−1. Further, lithium ions in the electrolyte were separated and recovered in the form of Li2CO3via simple chemical precipitation, highlighting the feasibility of the developed electrochemical system toward cobalt and lithium recovery. Significantly, the CC/KZHCF electrode materials could be regenerated through simple potential inversion, while adsorbed Co2+ ions were facilely desorbed from the electrode surface and recovered as Co(OH)2. This work will provide a meaningful guidance for the separation and recovery of various metals from waste LIBs.