Improved Cycling Stability of Li[Ni_0.90Co_0.05Mn_0.05]O₂ Through Microstructure Modification by Boron Doping for Li‐Ion Batteries

Abstract

Abstract Boron‐doped Li[Ni 0.90 Co 0.05 Mn 0.05 ]O 2 cathodes are synthesized by adding B 2 O 3 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 Li[Ni 0.90 Co 0.05 Mn 0.05 ]O 2 . The 1 mol% B‐Li[Ni 0.90 Co 0.05 Mn 0.05 ]O 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 °C, which is 15% higher than that of the undoped Li[Ni 0.90 Co 0.05 Mn 0.05 ]O 2 cathode. This proposed synthesis strategy demonstrates that an optimal microstructure exists for extending the cycle life of Ni‐rich Li[Ni 1‐ x ‐ y Co x Mn y ]O 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.