锂离子电池负极材料SnO2纳米单晶@硬炭的合成以及水系粘结剂对其电化学性能的影响  

Synthesis of anode material SnO/hard-carbon for Li-ion battery and effect of water binder on its electrochemical performance

作　　者：李玲芳[1] 曾斌[1] 原志朋 胡壮 范长岭[2] LI Lingfang;ZENG Bin;YUAN Zhipeng;HU Zhuang;FAN Changling(College of Mechanical Engineering,Hunan University of Arts and Science,Changde 415000,China;College of Materials Science and Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]湖南文理学院机械工程学院,湖南常德415000 [2]湖南大学材料科学与工程学院,长沙410082

出　　处：《功能材料》2020年第9期9208-9213,共6页Journal of Functional Materials

基　　金：国家自然科学基金项目(51802096,51672079,51972104);湖南省自然科学基金项目(2020JJ4449)。

摘　　要：在锂离子电池中,粘结剂的化学和物理性质极大地影响了电池的性能,对电极的完整性和界面反应性起着关键作用。水系粘结剂成本低廉,环境友好,且无需控制湿度,可能成为油性粘结剂聚偏二氟乙烯(PVDF)的可行替代品。首先以纤维素为碳源、SnCl4·5H2O为锡源,以水热法制备了具有纳米单晶结构的SnO2@硬炭复合物,分别利用X射线衍射(XRD)、扫描电镜(SEM)以及透射电镜(TEM)对其成分和微观结构进行表征。然后分别采用了PVDF和海藻酸钠为粘结剂制备了锂离子电池负极,并采用恒电流充放电测试探明了其电化学性能。结果显示,两种电极材料在小电流密度下容量均较高,展现了SnO2@硬炭复合物的容量优势。而海藻酸钠与SnO2@硬炭复合物的相容性更好,电极材料具有更好的倍率性能与循环性能,在2 A/g的大电流密度下具有约400 mAh/g的容量,100次循环后容量保持率为89%。拆卸电池后发现,以海藻酸钠为粘结剂的电极材料在循环多次后依然与集流体粘结紧密,这应是源于海藻酸钠中富含羧基,羧基能与SnO2形成络合物,能够形成更稳定的固态电解质膜,使得充放电过程更加稳定。In this paper,SnO2@hard-carbon composites with nano-single crystal structure were prepared by hydrothermal method by using cellulose as carbon source and SnCl4·5 H2O as tin source.Its composition and microstructure were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM).Then two anode electrodes were prepared by using PVDF and sodium alginate as binder respectively,and their electrochemical performance was confirmed by galvanostatic charge-discharge test.The results show that the compatibility of sodium alginate and SnO2@hard-carbon composite is better,and the electrode material has better rate performance and cycle performance.It has a capacity of about 400 mAh/g at high current density of 2 A/g,and the capacity retention is 89%after 100 cycles.After disassembling the coin cell,it was found that the electrode material with sodium alginate as binder still adhered colsely to the Cu foil after several cycles.Sodium alginate is rich in carboxyl groups,which can from a complex with SnO2 and make the charge-discharge process more stable.

关 键 词：SNO2 单晶 硬炭 水系粘结剂 海藻酸钠 

分 类 号：TM912.9[电气工程—电力电子与电力传动]