摘要
对于全固态锂离子电池,固态电解质是制约电池性能的最重要因素之一。以四氢呋喃为反应溶剂,以P_(2)S_(5),Li_(2)S和LiI为反应原材料,采用湿化学法及后续真空热反应方法成功制备出Li_(7)P_(2)S_(8)I固态电解质。通过同步热分析仪、粉末X射线衍射、拉曼光谱、扫描电子显微镜和能谱仪对所制备电解质样品的形貌、元素分布和物相组成进行表征分析。利用交流阻抗测试、循环伏安法和直流极化等手段研究了Li_(7)P_(2)S_(8)I固态电解质的电化学性能。不同温度对比分析结果表明Li_(7)P_(2)S_(8)I固态电解质的最佳热处理温度为230℃,在此条件下的制备产物具有纳米多孔结构且组成元素分布均匀。电化学测试表明该电解质在25℃下的离子电导率为1.63×10^(-4) S·cm^(-1),活化能为0.388 eV,电化学窗口达到5 V,锂离子迁移数高于0.999。该电解质与锂金属组装的对称电池可充放电稳定循环>262次(525 h),表明以此方法制备的Li_(7)P_(2)S_(8)I固态电解质与金属锂负极具有优异的电化学稳定性和化学相容性。
For advanced all-solid-state lithium batteries,the solid electrolyte is one of the most critical factors that significantly affect the performance of batteries.The Li_(7)P_(2)S_(8)I solid-state electrolyte was successfully prepared by wet-chemical synthesis and subsequent vacuum heat-treatment method,taking P_(2)S_(5),Li_(2)S and LiI as the raw materials and tetrahydrofuran as the reaction solvent.The morphology,elements distribution,and phase composition of the electrolyte sample were studied by means of simultaneous thermal analysis,powder X-ray diffraction,Raman spectroscopy,scanning electron microscope,and energy dispersive spectrometer.The electrochemical properties of Li_(7)P_(2)S_(8)I solid electrolyte were analyzed by AC impedance measurements,cyclic voltammetry,and DC polarization test.The results show that the optimal heat-treatment temperature of Li_(7)P_(2)S_(8)I solid electrolyte is 230℃ and the obtained sample has nanoporous structure and each kind of elements is uniformly distributed in it.Electrochemical tests show that the ionic conductivity of the electrolyte at 25℃ is 1.63×10^(-4)S·cm^(-1),the activation energy is 0.388 eV,the electrochemical window reaches 5 V and the lithium ion transport number is larger than 0.999.In addition,the symmetrical cell assembled with the electrolyte and lithium metal can be charged and discharged stably for more than 262 cycles(525 h).This proves that the Li_(7)P_(2)S_(8)I solid electrolyte prepared by this method has excellent electrochemical stability and chemical compatibility with the metal lithium anode.
作者
刘伟明
李久勇
张晓锋
马一博
韦友秀
张旋
颜悦
LIU Wei-ming;LI Jiu-yong;ZHANG Xiao-feng;MA Yi-bo;WEI You-xiu;ZHANG Xuan;YAN Yue(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Beijing Engineering Research Center of Advanced Structural Transparence for the Modern Traffic System,Beijing 100095,China;School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471000,Henan,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2021年第4期159-166,共8页
Journal of Materials Engineering
基金
国家自然科学基金项目(21603204)。
