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 (DLi+) of Li+ in SC electrode is calculated by CV is 2.2292×10-11 cm2·s-1, which is calculated by GITT and EIS ranges 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.