Effect of Magnesium Doping on Voltage Decay of Nickel‐Rich Cathode Materials

Structural degradation is the main challenge of Nickel‐rich cathodes, leading to capacity and voltage fading, especially at high cut‐off voltages. Herein, LiNi 0.94‐x Co 0.06 Mg x O 2 (x=0, 0.01, 0.02) samples have been prepared by high‐temperature solid‐state reaction method. The effects of Mg doping on its crystalline structure, and electrochemical performance have been studied by various characterizations analysis. We notice that Mg doping can not only tighten the structure/interface stability of the cathode, but also accelerates the Li + diffusion, thereby significantly achieving its high voltage/cycle stability. High‐voltage (4.5 V) electrochemical results show that Mg‐doped LiNi 0.94 Co 0.06 O 2 (1 % Mg) can achieve a high reversible capacity of 217.5 mAh g −1 at 0.2 C, high cycle retention rate of 80.5 % after 100 cycles at 0.2 C, inhibits average voltage decay, suppress resistance rise and boosted rate performance. Our work provides a solid strategy for improving the structure and voltage decay of nickel‐rich cathode materials for future high‐energy lithium‐ion batteries.