Effects of Ti4+ doping on electrochemical properties of LiNi0.815Co0.15Al0.035O2 cathode materials

The high nickel ternary cathode materials LiNi0.815Co0.15Al0.035O2 (NCA) have been widely used in Li-ion batteries due to their high energy density, low cost, and little environmental pollution. However, it suffers from rapid capacity degradation and poor charging rate. In this work, Ti4+ doping NCA cathode materials are prepared by the high-temperature solid-state method. The results show that 0.5%Ti-NCA has a lower cationic mixing degree and better cycling performance. The capacity retention rate of 100 cycles is 98.91% and 96.59% at current densities of 0.5 C and 1.0 C, respectively. The CV and EIS test results show that 0.5%Ti-NCA has lower polarization and higher lithium ion diffusion coefficient DLi+(8.43×10-14 cm2/S) after 100 cycles, while Pure-NCA only has 6.92×10-15 cm2/S, which effectively enhances the electrochemical properties of NCA cathode materials.