Enhanced Structural Stability and Electrochemical Performance of LiNi(0.6)Co(0.2)Mn(0.2)O(2) 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(0.6)Co(0.2)Mn(0.2)O(2) cathode materials are achieved by Ga doping. Compared with the pristine electrode, Li[Ni(0.6)Co(0.2)Mn(0.2)](0.98)Ga(0.02)O(2) 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(0.6)Co(0.2)Mn(0.2)O(2) cathode material.