活性物质比例及压实密度对NCM811正极的影响研究  

Study on the effect of active material ratio and compaction density on the positive electrode of NCM811

作　　者：单颖会 吴涛 林双 战祥连 SHAN Yinghui;WU Tao;LIN Shuang;ZHAN Xianglian(Zibo Torch Energy Co.,Ltd.,Zibo Shandong 255056,China)

机构地区：[1]淄博火炬能源有限责任公司,山东淄博255056

出　　处：《电源技术》2024年第1期71-78,共8页Chinese Journal of Power Sources

摘　　要：利用充放电机、交流阻抗技术、扫描电镜技术和半电池技术,研究了正极涂层中活性物质(NCM811)比例和涂层压实密度对正极的性能影响。相比于涂层中NCM811比例为90%和93.5%,当NCM811比例为97.3%时,活性物质放电比容量明显下降,这是因为导电剂不足,产生较强的欧姆极化所致;当NCM811比例为93.5%时,涂层放电比容量最高,是因为具有相对较少的非活性物质和相对较高的活性物质放电比容量;当NCM811比例为97.3%时,循环后NCM811颗粒出现粉碎化现象,这是各向异性应力和焦耳热共同作用的结果。涂层压实密度从3.325 g/cm^(3)到3.675 g/cm^(3),NCM811放电比容量先增后降,是欧姆极化和电化学极化共同作用的结果,循环稳定性逐渐提高,是因为辊压使涂层内部结构稳定,能抵抗活性物质各向异性应力以及降低极片欧姆电阻。The effects of the ratio of active substance(NCM811)in the positive electrode coating and the compaction density of the coating on the performance of the positive electrode were studied by using charge-discharge motor,AC impedance technology,SEM electron microscope technology and half-cell technology.Compared with 90%and 93.5%of NCM811 in the coating,when the ratio of NCM811 is 97.3%,the discharge specific capacity of the active substance is significantly reduced,which is due to the lack of conductive agent and strong ohmic polarization.When the ratio of NCM811 is 93.5%,the discharge specific capacity of the coating is the highest,because it has relatively less non-active substances and relatively high discharge specific capacity of active substance.When the ratio of NCM811 is 97.3%,the NCM811 particles appear pulverization after cycling,which is the result of the joint action of anisotropic stress and Joule heat.The compaction density of the coating increased from 3.325 g/cm3 to 3.675 g/cm3,and the discharge specific capacity of NCM811 increased at first and then decreased,which is the result of the joint action of ohmic polarization and electrochemical polarization.The cycle stability gradually improved,because rolling stabilized the internal structure of the coating,can resist anisotropic stress of active materials,and reduce the ohmic resistance of the electrode.

关 键 词：NCM811 活性物质比例 压实密度 粉碎化 

分 类 号：TM912[电气工程—电力电子与电力传动]