An innovative strategy for spent LiCoO2 battery recycling based on chemical looping complementary reduction

Abstract

The exponential development of new electric vehicles has led to the inevitable retirement of lithium-ion batteries as a power source. Recovery of spent lithium-ion batteries (LIBs) with remarkable resource and pollution characteristics is an essential solution to alleviate the shortage of lithium resources and drive the sustainable industrial development. Herein, a novel strategy was proposed as chemical looping complementary reduction (CLCR) for recycling valuable metals from spent LiCoO2 battery as chemical-looping cyclic carriers. The influencing factors of reduction temperature, time and H2 flows on reduction characteristics of LiCoO2 carriers were investigated on a laboratory-scale fixed bed. The results indicated that both high temperature and elevated H2 flows were conduce to enhancing LiCoO2 conversion with fairly high crystallinity and purity of reduction products (mainly Li2O and Co monomers) and 98.36 % conversion of LiCoO2 was attained at 1000 °C for 120 min with the H2 flow of 60 mL/min. Thermodynamic analysis proved that complementary matching properties existed between reduction temperature and H2 concentration affecting the phase equilibrium of products, while 650 °C ∼ 900 °C was favorable to obviate the formation of liquid LiOH and the loss of target products. Finally, the mechanism of CLCR along with its environmental and economic impacts were insightfully elaborated to provide a technical and cost-efficient scheme for spent LIBs recycling.