Submicron single-crystalline LiNi_(0.5)Mn_(1.5)O_(4) cathode with modulated Mn^(3+) content enabling high capacity and fast lithium-ion kinetics

摘要

Disordered single-crystalline LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode materials with different Mn^(3+)contents were prepared by a simple temperature control strategy of a solid-state reaction.The effects of the mutual modulation of the Mn^(3+) content and the bulk microstructure on the crystal structure and electrochemical properties of LNMO were systematically investigated.Results showed that a suitable Mn^(3+) content can enhance the structural stability and alleviate structural degradation and capacity fading.The excellent performance originates from the simultane-ous inhibition of microcrack formation and side reaction with electrolytes,ensuring the rapid diffusion of Li+during extraction and insertion.Consequently,the LNMO-800 sample delivers an excellent cycling stability with a capacity retention of 98.37%after 200 cycles,remarkable rate capacity of 115 mAh·g^(-1) at 10.0C,and rapid Li+diffusion coefficient of 4.43×10^(-9)cm^(2)·s^(-1).This work will allow for a deeper understanding of the coupling effect between Mn^(3+)content and bulk microstructure,especially in the design and development of Mn-based cathode materials.