铬氧化物作为高容量锂电池正极材料的制备及其性能研究  

Preparation and performance of high-capacity Cr_(8)O_(21)as a cathode material for lithium batteries

作　　者：孟庆飞 杨睿 金成龙 曹余良[2] 李文杰 周舟 吴际良 MENG Qingfei;YANG Rui;JIN Chengong;CAO Yuiang;LI Wenjie;ZHOU Zhou;WU Jiiang(Wuhan Zhongyuan Changjiang Technology Development Co.,Ltd.,Wuhan 430090,Hubei,China;College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,Hubei,China)

机构地区：[1]武汉中原长江科技发展有限公司,湖北武汉430090 [2]武汉大学化学与分子科学学院,湖北武汉430072

出　　处：《储能科学与技术》2023年第10期3049-3055,共7页Energy Storage Science and Technology

基　　金：国防基础科研计划资助(JCKY2021211B014)。

摘　　要：氧化铬(Cr_(8)O_(21))由于具有高比容量、高电压与低成本,成为高比能量锂电池正极材料的研究热点。本工作以CrO_(3)为前驱体,在氧气氛围下,通过一步煅烧法制得了高纯度的Cr_(8)O_(21)。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)以及电化学测试技术,对不同热解条件下产物的成分以及形貌进行了分析讨论,并对其作为锂电池正极材料的电化学性能进行了测试。研究结果表明,煅烧温度对氧化铬的电化学性能影响很大。较低温度下会有部分CrO_(3)未反应,电极容易被腐蚀损坏。而在较高的温度下,生成的Cr_(2)O_(5)杂相会降低电极材料的比容量。最终得到的优化条件为煅烧温度270℃,煅烧时间24 h,所得到的Cr_(8)O_(21)纯度最高且具备最佳的电性能。在0.1 C倍率下,首次放电可逆比容量高达357 mAh/g,平均放电电压为3 V。同时,对电池进行20周循环后,放电容量能保持在80%以上。最后,对所制备氧化铬的高低温放电性能也进行了研究,在-45℃和65℃下,其放电比容量分别为200 mAh/g和364 mAh/g,表明其具备良好的循环稳定性和电化学性能。Chromium oxide with high capacity,high voltage,and low cost has drawn much attention as a cathode material for lithium batteries.This study prepares high pure-phase Cr_(8)O_(21)through one-step pyrolysis under oxygen atmosphere with CrO_(3)as precursor.The chemical composition,morphology,and corresponding electrochemical performance of the samples prepared at different pyrolysis conditions are analyzed through X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,and electrochemical techniques.The results show that the pyrolysis temperature greatly affects the electrochemical performance of chromium oxides.The insufficient decomposition of CrO_(3)at lower temperatures results in electrode damage,and the impurity phase of Cr_(2)O_(5)formed during pyrolysis under higher temperatures significantly reduces the specific capacity.Cr_(8)O_(21)prepared at 270℃for 24 h exhibits an outstanding performance with a high specific capacity of 357 mAh/g at first discharge under 0.1 C and an average voltage reaching 3 V.The capacity retention exceeds 80%after a 20-cylce test.In addition,high specific capacities of 200 and 363 mAh/g are achieved at-45℃and 65℃,respectively,indicating the excellent cycling stability and electroactivity of Cr_(8)O_(21).

关 键 词：氧化铬 正极材料 锂电池 

分 类 号：TQ152[化学工程—电化学工业]