Sustainable regenerating of high-voltage performance LiCoO2 from spent lithium-ion batteries by interface engineering

Abstract

The LiCoO2 (LCO) material is extensively applied in Li-ion batteries due to its excellent property. Tons of LCO scraps is generated as the gradual abandonment of LIBs. Thus, it becomes extremely important to recycle the cathode material in order to protect the environment and utilize resources. This work proposes a direct recycling method of interface engineering to promote the high-voltage property of the regenerated LiCoO2. Adaptive hydrothermal relithiation is first performed to increase the missing Li+ of the used LiCoO2, and mechanically mixed with Li1.4Al0.4Ti1.6(PO4)3 (LATP) before annealing. It is discovered that, LiCoO2 can react with LATP when annealed at high temperature (> 700 °C), producing a mixed phase substance (Co3O4/Co2AlO4, CoTiO3 and Li3PO4) attaches to the surface of LiCoO2. These mixed phase substance can prevent interface reactions between the electrolyte and LiCoO2, thus improving the stability and the high-voltage property of regenerated LiCoO2. Compared to other recycling methods, the regenerated LiCoO2 possesses outstanding 4.4 V high-voltage property, with the initial discharging capacity of 166 mAh g−1 and the discharging capacity retention of 93.0% at 1C for 100 cycles.