Preparation of spherical LiNi_0.5Mn_1.5O₄ with core-multilayer shells structure by co-precipitation method and long cycle performance

¹ Heilongjiang Institute of Science and Technology, College of Environment and Chemical Engineering, NO. 2468 Puyuan Road, Harbin, 150022 China.
² Sinopec Shengli Petroleum Engineering Co., Ltd, No. 125, Jinan Road, Dongying, 257002 China.
³ Heilongjiang Institute of Energy and Environment, No. 15, Songshan Road, Harbin, 150000 China.

^* Corresponding author: 13089997952@163.com

Abstract

As a promising cathode material for lithium ion battemensionalry of high voltage, spinel LiNi_0.5Mn_1.5O₄ has attracted interest due to its high discharging voltage at 4.7 V and high energy density of 610 Wh kg^-1. In this work, LiNi0.5Mn1.5O₄ with a new core-multilayer shells structure (LNMO-900) is synthesized successfully by co-precipitation method and shows a better electrochemical performance. The formation of the core-multilayer shells structure is related to the kirkendall effect, the shell maintains structural stability, and improves long cycle performance. Core-multilayer shells structure is also beneficial for transmission of lithium ion, increasing rate performance. The effects of sintering temperature on the performance of LNMO were further investigated. Core-multilayer shells LiNi_0.5Mn_1.5O₄ is synthesized successfully at 900 °C for 12 h uniquely. From the integral calculation of XPS spectra, a higher content of Mn4+ is observed in the outer shell of LNMO-900 compared with other homogeneous solid particles. The discharge specific capacity of LNMO-900 is 129.3 mAh g^-1 at 1 C which is superior to others, and after 1000 cycles, LNMO-900 shows capacity retention of 87.9%. The initial capacity of LNMO-900 is 104.9 mAh g^-1 at 5 C.