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

Abstract

Rapid rejuvenation and extensive utilization of mobile electronic devices lead to the excessive accumulation of waste lithium-ion batteries (LIBs), especially represented by spent LiCoO2 cathode materials. Considering the shortage of metals resources and the surging price of raw materials in the battery industry, it is in urgent demand to exploit an efficient strategy for selectively extract valuable metals from spent LiCoO2. Herein, the nanocube-like potassium zinc hexacyanoferrate (denoted as KZHCF) has been successfully fabricated on carbon cloth (CC) substrate for selective Co2+ adsorption from spent LiCoO2 cathode via the combination of simple electrodeposition and hydrothermal treatment. Under the optimal operational conditions, 98.6% of Co2+ is effectively extracted within 120 min at a constant potential of −0.4 V (vs. Ag/AgCl) with CC/KZHCF composite as working electrode, accompanied by a Co2+ electrosorption capacity of 130.9 mg∙g−1. Further, lithium ions in the electrolyte are separated and recovered in the form of Li2CO3 via simple chemical precipitation, highlighting the feasibility of the developed electrochemical system toward cobalt and lithium recovery. Significantly, the CC/KZHCF electrode materials can be regenerated through simple potential inversion; while the adsorbed Co2+ ions are 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.