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

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]O2cathode 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 codoping,the obtained W-F-NCM95 cathodes deliver a high initial capacity of 236.1 mA h g-1at 0.1 C and superior capacity retention of 88.7% over 100 cycles at 0.5 C.Moreover,the capacity still maintains73.8% 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.