Excellent electrochemical performance of LiNi_0.5Co_0.2Mn_0.3O₂ with good crystallinity and submicron primary dispersed particles

Abstract

Nickel-cobalt-manganese ternary cathode materials are known as one of the most promising future cathode materials for Li-ion batteries (LIBs) due to their high discharge capacity, environmental friendliness, and low cost. In this paper, submicron LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) primary particles with good crystallinity and dispersibility have been synthesized combine a coprecipitation method used ethanol as solvent with solid-phase sintering technology. A feeding strategy through separate dropping of sodium carbonate and ammonia is adopted; the structure and properties of NCM523 under different pH conditions are investigated. It is found that the NCM523 synthesized at pH = 8 (NCM523-8) exhibits a uniform particle size of about 300 nm, with good crystallinity. The NCM523-8 exhibits an excellent high-potential cycling performance, with an initial discharge capacity of 193.6 mAh g −1 at 0.2 C in the voltage of 3.0 to 4.5 V, and the capacity retention is 91% after 100 cycles. It also shows excellent rate performance with a reversible capacity of 130 mAh g −1 at 5 C. The superior high-potential electrochemical performance is attributed to the improved lithium-ion diffusion coefficient and stabilized structure by the special structural characteristics as evidenced by cyclic voltammetry, electrochemical impedance spectroscopy, and X-ray diffraction. K E Y W O R D S crystallinity, high-potential performance, LiNi 0.5 Co 0.2 Mn 0.3 O 2 , lithium-ion battery, submicron particles 1 | INTRODUCTION Currently, Li-ion batteries (LIBs) have dominated portable electronic devices, electric vehicles (EVs), and energy storage fields due to their advantages such as high operating voltage, long lifespan , wide working temperature range, low self-discharge rate, and environmental friendliness. 1-5 The cathode materials, as an indispensable component of LIBs, determine the electrochemical performance of LIBs directly. 6-10 Nickel-cobaltmanganese (NCM) ternary cathode materials are known as one of the most promising future cathode materials for Yanfang Xie and Xinyi Dai contributed equally to this work.