Enhancement in electrochemical properties of sodium-doped LiNi0.815Co0.15Al0.035O2 cathode

Lithium-ion batteries (LIBs) as energy storage devices have been booming recently to fill the demand for energy requirements. High‑nickel ternary cathode material LiNi 0.815 Co 0.15 Al 0.035 O 2 (NCA), extremely possible to be the next generation of cathode materials for applications due to its high energy density , low cost, and environmental friendliness. However, the rate capability and cycling stability of this cathode material is mediocre. In this work, NCA-based cathode materials have been modified by sodium (Na + ) doping through a high-temperature solid-state reaction, the results show that Na + -doping can effectively improve the electrochemical performance of NCA. Electrochemical test results show that Na + -doping improves Li + diffusion coefficient , inhibits NCA polarization, and reduces the charge transfer impedance. As-prepared 2%Na-NCA at the current density of 1.0C shows a discharge-specific capacity of 149.16 mAh/g and a retention rate of 96.49% after 100 cycles, but the retention rate of the Pure-NCA was (84.47%). Furthermore, 2% Na-NCA shows 121.07 mAh/g at 5.0C, with an increase of 27.05 mAh/g over the Pure-NCA (94.02 mAh/g). The results of the study showed that doping with sodium ions can effectively improve the rate capabilities and cycling stability of NCA.