Efficient electrocatalytic formate oxidation on copper oxide catalyst mediated lithium recovery coupled hydrogen production

Abstract

In response to the increase in retired lithium-ion batteries (LIBs), there is a rising trend in lithium recycling, which can not only address the scarcity of lithium resources but also mitigate environmental pollution caused by battery waste. In this study, we present an electrocatalytic strategy for formate oxidation reaction (FOR) aimed at facilitating lithium recovery coupled hydrogen production. The obtained results have indicated that the synthesized Cu-based oxide can efficiently catalyze FOR, achieving a current density of 500 mA cm−2 at only 1.534 V vs. RHE. According to density functional theory calculations, the adsorption strength of the intermediate specie HCOO on Cu-based oxide is reduced (−0.36 eV) compared to Ni-based oxide (−2.27 eV), resulting in a thermodynamically favorable step for the rate-determining HCOO dehydrogenation reaction. Assembling a FOR coupled hydrogen evolution reaction (HER) electrolysis system can achieve hydrogen production and Li recovery (Li recovery product is Li2CO3) by electrolyzing alkaline raffinate containing lithium. This approach eliminates the need for additional formic acid and sodium carbonate, thereby reducing material consumption and ultimately enhancing the economic efficiency of the lithium battery recovery strategy.