Improved Cycling Stability of LiNi0.90Co0.05Mn0.05O-2 Through Microstructure Modification by Boron Doping for Li-Ion Batteries

摘要

Boron-doped LiNi0.90Co0.05Mn0.05O-2 cathodes are synthesized by adding B2O3 during the lithiation of the hydroxide precursor. Density functional theory confirms that boron doping at a level as low as 1 mol alters the surface energies to produce a highly textured microstructure that can partially relieve the intrinsic internal strain generated during the deep charging of LiNi0.90Co0.05Mn0.05O-2. The 1 mol B-LiNi0.90Co0.05Mn0.05O-2 cathode thus delivers a discharge capacity of 237 mAh g(-1) at 4.3 V, with an outstanding capacity retention of 91 after 100 cycles at 55 degrees C, which is 15 higher than that of the undoped LiNi0.90Co0.05Mn0.05O-2 cathode. This proposed synthesis strategy demonstrates that an optimal microstructure exists for extending the cycle life of Ni-rich LiNi1-x-yCoxMnyO-2 cathodes that have an inadequate cycling stability in electric vehicle applications and indicates that an optimal microstructure can be achieved through surface energy modification.