Renovation of LiCoO2 crystal structure from spent lithium ion batteries by ultrasonic hydrothermal reaction

Abstract

Used LiCoO2 material was renovated by means of ultrasound radiation under hydrothermal conditions. The optimal reaction condition for renovation process was obtained: temperature 120 °C, ultrasonic power 999 W, and ultrasonic method “work 5 s–stop 2 s” and ultrasonic radiation time 10 h. The XRD, SEM, ICP-AES analysis, and charge–discharge test showed that the renovated LiCoO2 had a high degree of crystallinity, a fine-layered structure, good dispersion of particles, and improved electrochemical cycle performance. The first-time charge capacity and discharge capacity of renovated LiCoO2 were 132.6 and 131.5 mAh/g, respectively. The first-time charge and discharge efficiency was 99.2 %. After 20 cycles, the discharge capacity retention rate was 98.1 % which reaches or approaches the electrochemical properties of commercial batteries.