Bifunctional Treatment of Spent Ternary Cathode Materials with Improved Electrochemical Performance

Rational reuse of spent lithium-ion battery (LIB) cathode materials is one of the research hotspots in the field of energy materials. Replenishment of Li in the spent LIB cathode material, which has suffered from extreme Li loss, has become an efficient strategy for regeneration of spent cathode materials. In this work, we present a facile method for regenerating the spent ternary cathode material LiNi0.5Co0.2Mn0.3O2 (NCM523) in the LiOH-Li2CO3 molten salt accompanied by TiO2 additive, in which the recovery of spent NCM523 and deposition of Li2TiO3 coating over the surface of the cathode materials have been realized in one step. It is found that the spent NCM523 can be regenerated in the LiOH-Li2CO3 molten salt at a lower temperature of 450 °C. Meanwhile, the Li2TiO3 coating can be formed over the surface of NCM523, which can boost the charge transfer and inhibit the dissolution of transition metal ions and side effects. As a cathode material for LIBs, the regenerated and Li2TiO3-coated NCM523 cathode materials exhibited a reversible capacity of 150.6 mAh g–1 at 1C, and the capacity retention reached 92% after 100 cycles. Especially, a reversible capacity of 120.5 mAh g–1 can be achieved at a high rate of 10 C. The method proposed opened up a process for bifunctional treatment of spent ternary cathode materials and can be applicable to the regeneration of other spent cathode materials.