Enhanced Structural Stability and Electrochemical Performance of LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Materials by Ga Doping

Structural instability during cycling is an important factor affecting the electrochemical performance of nickel-rich ternary cathode materials for Li-ion batteries. In this work, enhanced structural stability and electrochemical performance of LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials are achieved by Ga doping. Compared with the pristine electrode, Li[Ni_0.6Co_0.2Mn_0.2]_0.98Ga_0.02O₂ electrode exhibits remarkably improved electrochemical performance and thermal safety. At 0.5C rate, the discharge capacity increases from 169.3 mAh g^-1 to 177 mAh g^-1, and the capacity retention also rises from 82.8% to 89.8% after 50 cycles. In the charged state of 4.3 V, its exothermic temperature increases from 245.13 °C to more than 271.24 °C, and the total exothermic heat decreases from 561.7 to 225.6 J·g^-1. Both AC impedance spectroscopy and in situ XRD analysis confirmed that Ga doping can improve the stability of the electrode/electrolyte interface structure and bulk structure during cycling, which helps to improve the electrochemical performance of LiNi_0.6Co_0.2Mn_0.2O₂ cathode material.