Improve electrochemical performance of spinel LiNi_(0.5)Mn_(1.5)O_4 via surface modified by L_(1.2)Ni_(0.2)Mn_(0.6)O_2 layered materials

摘要

Spinel LiNi_(0.5)Mn_(1.5)O_4(LNMO) is one of the most promising cathode materials for lithium-ion batteries due to its high operating voltage (4.7 V, vs. Li / Li~+). However, the high operating voltage will cause the LNMO capacity to decay due to the dissolution of its Mn and the decomposition of the electrolyte. Although surface modification can improve the cycle stability of LNMO, most of the current surface modification will cause different degrees of loss in discharge capacity. Herein, for the first time, Li_(1.2)Ni_(0.2)Mn_(0.6)O_2(LIR) is coated on the host material LNMO as the surface material by co-precipitation method. As the coating materials, LIR does not destroy the crystal structure and micromorphology of LNMO. The surface-modified material (LNMO@LIR) has higher reversible capacity with better cycle stability than LNMO. The LNMO@LIR delivers a discharge capacity of 128.32 mAh g~(-1) at 0.5 ℃, and the capacity retention rate is up to 97.2% after 300 cycles. This work indicates that LIR coating can efficiently enhance the electrochemical performance of LNMO.