(1. 吉首大學(xué) 生物資源與環(huán)境科學(xué)學(xué)院，吉首 416000；
2. 中南大學(xué) 化學(xué)化工學(xué)院，長沙 410083)
摘 要: 采用流變相法合成LiNi0.5Mn1.5O4粉末。以甲醛為還原劑，采用化學(xué)鍍法制備LiNi0.5Mn1.5O4/Ag復(fù)合材料。通過X射線衍射分析、掃描電鏡分析以及電化學(xué)測試等手段對LiNi0.5Mn1.5O4/Ag的微觀結(jié)構(gòu)、表面形貌和電化學(xué)性能進(jìn)行研究。結(jié)果表明：在LiNi0.5Mn1.5O4/Ag中，LiNi0.5Mn1.5O4表面被包覆一層分散均勻且顆粒大小均勻的Ag，Ag顆粒的大小為200~300 nm。Ag顆粒的存在增加LiNi0.5Mn1.5O4顆粒之間的電子導(dǎo)電性，降低電池的極化作用，減少錳的溶解，使得LiNi0.5Mn1.5O4/Ag具有比LiNi0.5Mn1.5O4更高的可逆容量、更穩(wěn)定的循環(huán)性能和更好的倍率性能。以0.2C放電時(shí)，LiNi0.5Mn1.5O4/Ag的首次放電容量達(dá)到143.8 mA∙h/g；而經(jīng)100次循環(huán)后，以0.2C和2.0C放電時(shí)，LiNi0.5Mn1.5O4/Ag的容量保持率分別達(dá)到99.2%和86.8%。
關(guān)鍵字: 鋰離子電池；LiNi0.5Mn1.5O4；銀；包覆；化學(xué)鍍
LiNi0.5Mn1.5O4/Ag composite
（1. College of Biology and Environmental Science, Jishou University, Jishou 416000, China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:LiNi0.5Mn1.5O4 powders were prepared by rheological method. LiNi0.5Mn1.5O4/Ag composite was prepared by electroless plating method using formaldehyde as reductant. The microstructure, surface morphology and electrochemical properties of LiNi0.5Mn1.5O4/Ag composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. The phase analysis shows that Ag particles with a uniform size of 200−300 nm are dispersed on the surface of LiNi0.5Mn1.5O4 instead of entering the spinel structure. According to the electrochemical tests results, it is clear to see that Ag additives efficiently improve the cycling stability, reversibility and high-rate discharge capacity of pristine LiNi0.5Mn1.5O4 by increasing the electrical conductivity between LiNi0.5Mn1.5O4 particles, decreasing the polarization of cathode and reducing the dissolution of Mn. The first discharge capacity of LiNi0.5Mn1.5O4/Ag composite is higher than 143.8 mA∙h/g at 0.2C. After cycling 100 times at 0.2C and 2.0C, the capacity retention of LiNi0.5Mn1.5O4/Ag composite are 99.2% and 86.8%, respectively.
Key words: Li ions battery; LiNi0.5Mn1.5O4; Ag; coating; electroless plating
