Element doping induced microstructural engineering enhancing the lithium storage performance of high-nickel layered cathodes

Abstract

The high-nickel layered cathodes Li[NixCoyMn1−x−y]O2 (x ≥ 0.8) with high specific capacity and long cycle life are considered as prospective cathodes for lithium-ion batteries. However, the microcrack formation and poor structural stability give rise to inferior rate performance and undesirable cycling life. Herein, we propose a dual modification strategy combining primary particle structure design and element doping to modify Li[Ni0.95Co0.025Mn0.025]O2 cathode by tungsten and fluorine co-doped (W-F-NCM95). The doping of W can convert the microstructure of primary particles to the unique rod-like shape, which is beneficial to enhance the reversibility of phase transition and alleviate the generation of microcracks. F doping is conducive to alleviating the surface side reactions. Thus, due to the synergistic effect of W, F co-doping, the obtained W-F-NCM95 cathodes deliver a high initial capacity of 236.1 mA h g−1 at 0.1 C and superior capacity retention of 88.7% over 100 cycles at 0.5 C. Moreover, the capacity still maintains 73.8% after 500 cycles at 0.5 C and the texture of primary particle is intact. This work provides an available strategy by W and F co-doping to enhance the electrochemistry performance of high-nickel cathodes for practical application.