摘要
采用氧化铝修饰改性富锂锰基正极材料,探讨了表面活性剂在修饰改性中的作用。利用扫描电子显微镜、X射线衍射仪、透射电子显微镜和电化学性能测试等方法对材料结构和电化学性能进行分析。实验结果表明,十二烷基三甲基溴化铵(DTAB)能使Al_2O_3纳米颗粒均匀包覆在富锂锰基正极材料表面,有效增强了复合材料结构的稳定性。在600 mA·g^(-1)电流密度下,该复合材料的初始放电容量为186mAh·g^(-1)。经过500次循环后,其可逆放电比容量仍高于132 mAh·g^(-1),初始容量保持率高达71%。此外,电压衰退也被有效抑制,复合材料表现出优异的综合电化学性能。
In this work, a series of Li-rich layered metal oxides （LLMO） were prepared by the coprecipitation method for use as cathode materials in lithium ion batteries. Various surfactants were used for the preparation of Al2O3-modified LLMO. The roles of surfactants were systematically investigated to reveal the mechanism of Al2O3 modification. The microstructure and morphology of the as-prepared samples were studied by the X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The electrochemical performance was evaluated by means of cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The experimental results showed that Al2O3 nanoparticles were uniformly dispersed on the LLMO surface using N,N,N-trimethyl-l-dodecanaminium bromide （DTAB） as the surfactant, to obtain an initial discharge capacity of 186 mAh.g-1 at the current density of 600 mA.g-1. After 500 cycles, the reversible discharge capacity was 132 mAh.g-1 with a satisfactory capacity retention of 71%. Moreover, the voltage fading of the LLMO was greatly suppressed after Al2O3 modification. Therefore, the Al2O3-modified LLMO exhibited superior electrochemical performances compared with unmodified LLMO.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2017年第6期1189-1196,共8页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(21403196
51572240
51677170)
浙江省自然科学基金(LY15B030003
LY16E070004
LY17E020010)
福特汽车公司高校研究项目资助~~
关键词
表面活性剂
锂离子电池
正极材料
氧化铝
富锂锰材料
Surfactant
Lithium-ion battery
Cathode material
Aluminum oxide
Li-rich layered metal oxide
作者简介
Corresponding author. Email： echem@zjut.edu.cn; Tel： ＋86-571-88320873.
