摘要
溶剂热法可控合成NiCo_(2)O_(4)锂电池负极材料,进行XRD、ESEM、电化学性能分析并获得分散性好、晶型完整的尖晶石型NiCo_(2)O_(4)纳米片。充放电测试显示:首次比容量分别为1376mAh/g和1544mAh/g;经150次循环后,容量保持率约70%。低倍率下(0.05~2C)稳定性明显高于高倍率(10C)下,与Li+在电解液中的扩散电阻增大有关,这在交流阻抗(EIS)中得到证实。循环伏安(CV)为进一步弄清脱嵌锂机理提供了依据。EIS等效电路拟合结果显示:60次循环后,电极电阻(R1)由357Ω·cm^(2)下降到154Ω·cm^(2),与电极材料活化有关。但电解液扩散电阻(WS)从345Ω·cm^(2)增大到467Ω·cm^(2),与电极材料被破坏粉化有关。为了更好平衡这两个相互矛盾的变量,有效控制合成NiCo_(2)O_(4)电极材料十分关键,本法获得的NiCo_(2)O_(4)负极材料其电化学性能较优异。
NiCo_(2)O_(4)anode materials for lithium battery was controllably synthesized by solvothermal method.XRD,ESEM and electrochemical properties were analyzed and spinel NiCo_(2)O_(4)nanosheets with good dispersion and complete crystals were obtained.Charge-discharge test show that the initial capacities are 1376mAh/g and 1544mAh/g,respectively;After 150cycles,the retention rate is about 70%.Stability at low rate(0.05C)is obviously higher than that at high rate(10C),it might be relate to the diffusion resistance of Li+in the electrolyte,which is confirmed by electrochemical impedance analysis(EIS).Cyclic voltammetry(CV)is carried to further understand the mechanism of lithium de-embedding.Results of equivalent circuit fitting in EIS analysis showed that the electrode resistance(R1)decreased from 357Ω·cm^(2)to 154Ω·cm^(2)after 60cycles,it was related to the activation of electrode materials.However,the electrolyte diffusion resistance(Ws)increased from 345Ω·cm^(2)to 467Ω·cm^(2)at the same condition,it was related to being destroyed and pulverized of the electrode materials.So it is critical to effectively control synthesis of NiCo_(2)O_(4)electrode materials in order to better balance the two contradictory variables.Excellent electrochemical properties of NiCo_(2)O_(4)material are obtained by this method.
作者
华丽
曾建华
樊锋凯
朱玉涵
翁方青
胡庆兰
李景蕻
HUA Li;ZENG Jian-hua;FAN Feng-kai;ZHU Yu-han;WENG Fang-qing;HU Qing-lan;LI Jing-hong(School of Chemistry and Life Science,Hubei University of Education,Wuhan 430205,China;Hubei Key Laboratory of Purification and Application of Anticancer Active Substances,Wuhan 430205,China)
出处
《武汉理工大学学报》
CAS
2022年第11期19-25,共7页
Journal of Wuhan University of Technology
基金
湖北省自然科学基金(2021CFB251)
国家自然科学基金青年项目(22004029)
湖北第二师范学院校级教学研究和科学研究项目(X2019013,X2020001和20XGZX10).
