Fast Li-ion conductor Li1+yTi2-yAly(PO4)3 modified Li1.2[Mn0.54Ni0.13Co0.13]O2 as high performance cathode material for Li-ion battery

Abstract

In the material of xLi2MnO3 ·(1-x) LiMO2 (0 < x < 1), the Li2MnO3 component is used to stabilize the layered LiMO2 structure. However, the electrochemical inactive Li2MnO3 makes Li-ion diffusion difficult, leading to a sluggish rate capability. In this work, Li1.3Ti1.7Al0.3(PO4)3 (LTA0.3), a NASICON-type Li-ion conductor, is applied to modified Li1.2Mn0.54Ni0.13Co0.13O2 to overcome the above shortcoming. Additionally, the Li-ion conductivity of LiTi2(PO4)3 can be improved effectively by replacing tetravalent cation Ti4+ with trivalent Al3+ at the optimal ratio. At 1C rate, the LR cathode with 3 wt% LTA0.3 delivers 200 mAh g−1 after 170 cycles and maintains 140 mAh g−1 after 500 cycles. Moreover, the modified cathode shows an enhanced rate performance of 169.7 mAh g−1 at 5C. Enhanced cycle durability and rate capability are aroused by the 3D skeletal framework of LTA0.3, which is suitable for Li-ion diffusion. The LTA0.3 coating layer displays a robust shell which not only avoids the corrosion of electrode materials but also effectively facilitates Li-ion diffusion.