Three-dimensional Li-ion transportation in Li2MnO3-integrated LiNi0.8Co0.1Mn0.1O2

Ni-rich layered cathodes(LiNixCoyMn2O2) have recently drawn much attention due to their high specific capacities.However,the poor rate capability of LiNixCoyMn2O2,which is mainly originated from the twodimensional diffusion of Li ions in the Li slab and Li~+/Ni2+cation mixing that hinder the Li~+diffusion,has limited their practical application where high power density is needed.Here we integrated Li2MnO3nanodomains into the layered structure of a typical Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811) material,which minimized the Li~+/Ni2+cationic disordering,and more importantly,established grain boundaries within the NCM811 matrix,thus providing a three-dimensional diffusion channel for Li ions.Accordingly,an average Li-ion diffusion coefficient(DLi+) of the Li2MnO3-integrated LiNi0.8Co0.1Mn0.1O2(NCM811-I) during charge/discharge was calculated to be approximately 6*10-10cm~2 S-1,two times of that in the bare NCM811(3*10-10cm~2 S-1).The capacity delivered by the NCM811-I(154.5 mAh g-1) was higher than that of NCM811(141.3 mAh g-1) at 2 C,and the capacity retention of NCM811-I increased by 13.6% after100 cycles at 0.1 C and 13.4% after 500 cycles at 1 C compared to NCM811.This work provides a valuable routine to improve the rate capability of Ni-rich cathode materials,which may be applied to other oxide cathodes with sluggish Li-ion transportation.