Diffusion coefficient analysis of aluminum electrolysis spent cathode as anode material for lithium-ion battery

The aluminum electrolysis spent cathode (SC) was treated by hydrothermal method and used as anode material for lithium-ion battery. The purified SC material shows excellent electrochemical performance. In order to understand the diffusion behavior of Li+ in the SC electrode, the diffusion coefficient of Li+ in the SC electrode was systematically analyzed by galvanostatic intermittent titration technique (GITT), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results show that the diffusion coefficient ( $${D}_{{\text{Li}}^{+}}$$ ) of Li+ in SC electrode is calculated by CV is 2.2292 × 10−11 cm2 s−1, and the ranges calculated by GITT and EIS are 4.2286 × 10−13 − 2.9667 × 10−10 cm2 s−1, 4.05 × 10−13 − 3.87 × 10−12 cm2 s−1, respectively. SC electrode exhibits better Li+ diffusion kinetics compared to commercial graphite (CG). In addition, the full cell of LiNi0.5Co0.2Mn0.3O2/SC also shows excellent cycle performance. After 80 cycles at 1 °C (1 °C = 172 mA g−1), the specific discharge capacity of LiNi0.5Co0.2Mn0.3O2/SC full-cell can reach 94.7 mAh g−1, and the capacity retention can reach 98.13%. The fast lithium-ion diffusion rate and high discharge capacity provide a feasible direction for the high value utilization of aluminum electrolysis spent cathode.