“…The recovery rate of hydrometallurgy is far from that of pyrometallurgy. In the acid leaching of electrode materials, inorganic acids are mostly used, usually including hydrochloric acid (HCl) (Li et al, 2009;Guo et al, 2016;Barik et al, 2017), sulfuric acid (H 2 SO 4 ) (Dun-Fang et al, 2009;Meshram et al, 2015Meshram et al, , 2016, nitric acid (HNO 3 ) (Li et al, 2011;Mossini et al, 2015), and phosphoric acid (H 3 PO 4 ) (Pinna et al, 2016;Chen et al, 2017), while the organic acids studied include citric acid (Li et al, 2010;Gao et al, 2019;Yu et al, 2019), oxalic acid (Zeng et al, 2015), and tartaric acid (Chen et al, 2019). Lee and Rhee (2003) used HCl to recycle LiCoO 2 and revealed the principle of acid leaching:…”