(中南大學(xué) 化學(xué)化工學(xué)院，長(zhǎng)沙 410083)
摘 要: 基于電化學(xué)還原技術(shù)，提出在低酸度溶液中電解浸出廢舊鋰離子電池正極片(LiCoO2)的新方法。線性伏安掃描結(jié)果表明：LiCoO2的還原峰電位為0.30 V(vs SCE)，驗(yàn)證了此方法的可行性。通過(guò)條件實(shí)驗(yàn)對(duì)影響鈷和鋁浸出率的各因素進(jìn)行考察，得到電解浸出的最佳條件：電流密度15.6 mA/cm2、硫酸濃度40 g/L、檸檬酸濃度36 g/L、溫度45 ℃、時(shí)間120 min。在此優(yōu)化條件下，鈷和鋁的浸出率分別為90.8%和7.9%。電解浸出后，可直接回收鋁箔，用掃描電子顯微鏡(SEM)對(duì)鋁箔表面進(jìn)行觀察，結(jié)果表明：鋁箔在浸出過(guò)程中的腐蝕深度遠(yuǎn)小于其表面原有點(diǎn)蝕坑的深度。
關(guān)鍵字: 廢舊鋰離子電池；LiCoO2；電化學(xué)還原；電解浸出；陰極保護(hù)
（School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:Based on the electrochemical reduction technique, a novel process was developed for leaching LiCoO2 in the low acidity medium by electrolysis from spent lithium-ion secondary batteries. The electrochemical deoxidizing of LiCoO2 was characterized by linear sweeping voltammetry. The results show that the cathodic peak potential of LiCoO2 is 0.30 V(vs SCE), which verifies the possibility of the process. The related factors on the leaching rates of Co and Al were investigated by single factor experimental method, and the optimal parameters are as follows: current density 15.6 mA/cm2, concentration of H2SO4 40 g/L, concentration of C6H8O7？H2O 36 g/L, reaction temperature 45 ℃, electrolysis time 120 min. Under the optimal conditions, the leaching rates of Co and Al are 90.8% and 7.9%, respectively. After leaching, the aluminum foil can be recovered in their metallic forms. The surface morphology of the aluminum foil was examined by scanning electron microscopy (SEM). The results indicate that the corrosion depth of aluminum foil under leaching conditions is much smaller than the corrosive pit depth of aluminum foil without leaching in the sulfuric acid solution.
Key words: spent lithium-ion battery; LiCoO2; electrochemical reduction; electrolysis leaching; cathodic protection
