Surface modification of Li rich Li1.2Mn0.54Ni0.13Co0.13O2 cathode particles

Li-rich Mn-based layered oxide Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) has received great interest due to its high discharge capacity. However, the fast capacity attenuation seriously hinders its wide application. LMNCO particles are synthesized via a co-precipitation method. To enhance the cycle stability, (Ni0.4Co0.2Mn0.4)(1-x)Ti-x(OH)(2+2x) surface layer is deposited on LMNCO precursor particles by a second co-precipitation process. Due to the mutual diffusion of elements during sintering, Ti is distributed in the 2-3 mu m shell of particles. The cells are cycled in a voltage window of 2.0-4.8 V at 0.5C. After 200 cycles, LMNCO exhibits a capacity retention of 43%, and LMNCO particles have been pulverized by the cycle process. In contrast, the structural integrity of coated particles is maintained, and therefore the cycle stability is evidently improved.