摘要
采用两步加热Polyol法制备了纳米LiMnPO4正极材料,详细研究了第一加热平台温度T1(T1=100,110,120,130,140,150°C)对样品物理性质及电化学性能的影响.通过X射线衍射(XRD)、扫描电镜(SEM)及比表面积测试(BET)对样品的晶体结构与微观形貌进行了表征.结果表明,在不同温度T1下得到的样品均为片状结构;T1=100-120°C时合成的样品含有杂相,且比表面积小于15 m2?g-1;在T1=130°C时,得到纯相LiMnPO4样品,且比表面积增至46.3 m2?g-1;随着T1的进一步升高,样品比表面积稍有下降,维持在35-37 m2?g-1之间.纳米LiMnPO4的电化学性能变化趋势与比表面积基本一致,T1=130°C时合成的样品呈现最优的电化学性能,在0.1C倍率下放电容量达到129 mAh?g-1,在5C倍率时达到81 mAh?g-1,这表明LiMnPO4的比表面积是决定其电化学性能的关键因素之一.
Nano-LiMnPO4 samples were synthesized via a two-step heating polyol method. The role of the first thermal plateau temperature T1 （T1=100, 110, 120, 130, 140, 150 ＆#176;C） on the physical and electrochemical properties of the samples was investigated. Their structures and morphologies were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and N2 sorption measurements. Al samples at different plateau temperatures exhibited a sheet structure. At T1=100-120 ＆#176;C, samples contained some impurities, and their specific surface areas were＆lt;15 m2？g-1. Pure nano-LiMnPO4 was obtained at T1=130 ＆#176;C, and exhibited the largest specific surface area （46.3 m2？g-1）. The specific surface areas of samples remained at 35-37 m2？g-1 with further increase in T1. The electrochemical performance of the nano-LiMnPO4 samples fol owed the same trend as their specific surface areas. Nano-LiMnPO4 at T1=130 ＆#176;C exhibited the best electrochemical performance, with a discharge capacity of 129 mAh？g-1 at 0.1C rate and 81 mAh？g-1 at 5C rate. This indicated that the specific surface area is one of the key factors in determining the electrochemical performance of LiMnPO4.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2014年第3期460-466,共7页
Acta Physico-Chimica Sinica
基金
浙江省钱江人才计划(2012R10078)
武汉-中科院院地合作项目(20120216)
国家自然科学基金项目(51372228)资助~~
