Improving the structure and cycling stability of Ni-rich cathodes by dual modification

The irreversible phase transition and interface side reactions during the cycling process severely limit the large-scale application of nickel-rich layered oxides Li[Ni_xCo_yMn_1−x−y]O₂ (NCM, x>0.8). Herein, we have designed LiNi_0.8Co_0.1Mn_0.1O₂ cathodes modified by Nb/Al co-doping and LiNbO₃/LiAlO₂ composite coating. Detailed characterization reveals that Nb/Al co-doping can stabilize the crystal structure of the cathodes and expand the layer spacing of the layered lattice, thereby increasing the diffusion rate and reversibility of Li⁺. And the composite coatings can improve the electrochemical kinetic and inhibit the erosion of acidic substances by hindering direct contact between the cathodes and electrolyte. As a result, the Ni-rich cathodes with dual modification can still exhibit a higher capacity of 184.02 mA·h/g after 100 cycles with a capacity retention of up to 98.1%, and can still release a capacity of 161.6 mA·h/g at a high rate of 7C, meanwhile, it shows excellent thermal stability compared to bare NCM. This work provides a new perspective for enhancing electrochemical properties of cathodes through integrated strategies.