近球形MoS_(2)负极材料的强化水热合成与电化学性能  

Enhanced Hydrothermal Synthesis and Electrochemical Performance of Subsphaeroidal MoS_(2)used as Anode Material for Lithium-Ion Batteries

作　　者：吴杨 张亮亮 王伟 范东昇 杨慎慎 白云豪 李继文[1] 刘伟[1,3] Wu Yang;Zhang Liangliang;Wang Wei;Fan Dongsheng;Yang Shenshen;Bai Yunhao;Li Jiwen;Liu Wei(School of Material Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China;Zhuhai CosMX Battery Co.,Ltd,Zhuhai 519580,China;Collaborative Innovation Center for New Materials and Advanced Processing Technologies of Nonferrous Metals,Luoyang 471023,China)

机构地区：[1]河南科技大学材料科学与工程学院,河南洛阳471023 [2]珠海冠宇电池股份有限公司,广东珠海519580 [3]有色金属新材料与先进加工技术省部共建协同创新中心,河南洛阳471023

出　　处：《稀有金属材料与工程》2023年第8期2893-2900,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(U1704152);河南省高等学校重点科研项目(20A430011);河南省高等学校青年骨干教师培养计划(2019GGJS073);河南科技大学大学生研究训练计划(2022033)。

摘　　要：分别以钼酸铵和硫脲为钼源和硫源,在聚乙烯吡咯烷酮(PVP)软模板作用下,采用强化水热法在较短时间内制备出了近球形纯MoS_(2)粉体材料。通过X射线衍射(XRD)、钨灯丝扫描电镜(SEM)、场发射扫描电镜(FESEM)、高分辨透射电镜(HRTEM),X射线光电子能谱(XPS)等表征方法,研究了近球形纯MoS_(2)材料的微观形貌、晶体结构、元素组成及表面价态。结果表明:所制备得到的MoS_(2)材料为由片状二硫化钼所构成的球体,尺寸为150 nm左右,经过500℃加热处理2h后,微观形貌不变。经过恒流充放电测试,其在500mA/g的电流密度下,加热处理前的MoS_(2)材料首次放电比容量高达874.7 mAh/g,但存在较大的容量衰减,其循环充放电100次后容量保持率仅为53.3%,并且其首次充放电库伦效率仅为68.88%,直到第47次充放电时才稳定在100%;而经过500℃加热处理2h后的MoS_(2)材料充放电的容量损失较小,循环稳定性增强,经过100次充放电后容量达571.3 mAh/g,容量保持率为83.2%,且库伦效率一直为100%稳定不衰减。加热处理后性能提升的原因一方面在于材料中残留氧化钼挥发,材料内部出现部分空隙,从而增大了活性物质与电解液的接触面积。另一方面加热处理提高了材料的结晶性,可以稳定MoS_(2)的晶体结构,抑制嵌锂-脱嵌过程中的体积膨胀问题。Subsphaeroidal MoS_(2)anode powder material with good electrochemical performance for lithium-ion batteries(LIBs)was synthesized by enhanced hydro thermal process(EHP)in relatively short reaction time.The ammonium molybdate,thiourea and polyvinyl pyrrolidone(PVP)were used as molybdenum source,sulfur source and soft mold surfactant,respectively.The crystal structure,morphology,element component and valencies of the as-prepared samples were characterized by XRD,SEM,FESEM,TEM,HRTEM and XPS.Galvanostatic charge-discharge,cyclic voltammetry and electrochemical impedance spectroscopy tests were conducted to evaluate the electrochemical performance of the batteries prepared by the as-prepared powder.The experimental results show that the as-prepared powder is subsphaeroidal MoS_(2)particle with average grain size of about 150 nm.After annealing at 500°C for 2 h,there is no significant change in morphology.As anodes for LIBs,subsphaeroidal MoS_(2)without annealing exhibits relatively high initial discharge capacity of 874.7 mAh/g at current density of 500 mA/g,which gradually decays in the following cycles.The capacity retention rate after 100 cycles is only 53.3%.As a contrast,the electrochemical properties are enhanced for the counterparts after annealing,which exhibits an ultimate(100 cycles)discharge capacity of 571.3 mAh/g and a capacity retention rate of 83.2%.The coulomb efficiency of samples without annealing for the first cycle is only 68.88%and increases afterwards to 100%at the 47th cycle.For the specimens after heat treatment at 500°C for 2 h,the coulomb efficiency is 100%in the initial stage and does not decrease in the following cycles,which indicates a small capacity loss of charge-discharge efficiency and the stable cycle performances.The performance enhancement of the annealed specimens is attributed to the following reasons.The residual molybdenum oxide in the material evaporates during annealing,resulting in some voids inside the material,which increases the contact area between the active substance

关 键 词：锂离子电池 负极材料 强化水热法 近球形MoS_(2) 

分 类 号：TM911[电气工程—电力电子与电力传动]