Alleviating structural degradation of nickel-rich cathode material by eliminating the surface Fm[formula omitted]m phase

Abstract

Nickel-rich LiNixM1-xO2 (M=Co, Mn or Al, x>0.6) oxide owns high capacity and energy density as cathode material for Li-ion batteries. However, the severe structural decay during cycling impedes its commercialization. In our work, the rock-salt Fm 3¯ m phase on the LiNi0.8Co0.1Mn0.1O2 particle surface which can induce the structural instability during cycling is inhibited to produce: LiNi0.71Co0.09Mn0.2O2 cathode material composes of a uniform layered R3¯m phase with a self-assembled concentration-gradient shell is prepared using Mn precursor coating on Ni0.8Co0.1Mn0.1(OH)2. This material shows enhanced structural stability due to the removal of Fm 3¯ m phase, contributing to capacity retention of 92.2% after 100 cycles at 0.1C rate between 2.8 and 4.5V. In addition, the thermal stability is also improved after the elimination of Fm3¯m phase.