Effect of LiTFSI and LiFSI on Cycling Performance of Lithium Metal Batteries Using Thermoplastic Polyurethane/Halloysite Nanotubes Solid Electrolyte
来源期刊：Acta Metallurgica Sinica2021年第3期
论文作者：Zhichuan Shen Jiawei Zhong Wenhao Xie Jinbiao Chen Xi Ke Jianmin Ma Zhicong Shi
文章页码：359 - 372
摘 要：All-solid-state lithium batteries（ASSLB） are promising candidates for next-generation energy storage devices.Nevertheless,the large-scale commercial application of high energy density AS S LB with the polymer electrolyte still faces challenges.In this study,a thin solid polymer composite electrolyte（SPCE） is prepared through a facile and cost-effective strategy with an infiltration of thermoplastic polyurethane（TPU）,lithium salt（LiTFSI or LiFSI）,and halloysite nanotubes（HNTs） in a porous framework of polyethylene separator（PE）（TPU-HNTs-LiTFSI-PE or TPU-HNTs-LiFSI-PE）.The composition,electrochemical performance,and especially the effect of anions（TFSI-and FSI-） on cycling performance are investigated.The results reveal that the flexible TPU-HNTs-LiTFSI-PE and TPU-HNTs-LiFSI-PE with a thickness of 34 μm exhibit wide electrochemical windows of 4.9 and 5.1 V（vs.Li+/Li） at 60℃,respectively.Reduction in FSI-tends to form more LiF and sulfur compounds at the interface between TPU-HNTs-LiFSI-PE and Li metal anode,thus enhancing the interfacial stability.As a result,cell composed of TPU-HNTs-LiFSI-PE exhibits a smaller increase in interfacial resistance of solid electrolyte interphase（SEI） with a distinct decrease in charge-transfer resistance during cycling.Li|Li symmetric cell with TPU-HNTs-LiFSI-PE could keep its stable overpotential profile for nearly 1300 h with a low hysteresis of approximately39 mV at a current density of 0.1 mA cm-2,while a sudden voltage rise with internal cell impedance-surge signals was observed within 600 h for cell composed of TPU-HNTs-LiTFSI-PE.The initial capacities of NCMITPU-HNTs-LiTFSIPEILi and NCMITPU-HNTs-LiFSI-PEILi cells were 149 and 114 mAh g-1,with capacity retention rates of 83.52% and89.99% after 300 cycles at 0.5 C,respectively.This study provides a valuable guideline for designing flexible SPCE,which shows great application prospect in the practice of ASSLB.
Zhichuan Shen1,2，Jiawei Zhong1,2，Wenhao Xie1,2，Jinbiao Chen1,2，Xi Ke1,2，Jianmin Ma3，Zhicong Shi1,2
1. School of Materials and Energy,Guangdong University of Technology2. Guangdong Engineering Technology Research Center for New Energy Materials and Devices3. School of Physics and Electronics,Hunan University
摘 要：All-solid-state lithium batteries（ASSLB） are promising candidates for next-generation energy storage devices.Nevertheless,the large-scale commercial application of high energy density AS S LB with the polymer electrolyte still faces challenges.In this study,a thin solid polymer composite electrolyte（SPCE） is prepared through a facile and cost-effective strategy with an infiltration of thermoplastic polyurethane（TPU）,lithium salt（LiTFSI or LiFSI）,and halloysite nanotubes（HNTs） in a porous framework of polyethylene separator（PE）（TPU-HNTs-LiTFSI-PE or TPU-HNTs-LiFSI-PE）.The composition,electrochemical performance,and especially the effect of anions（TFSI-and FSI-） on cycling performance are investigated.The results reveal that the flexible TPU-HNTs-LiTFSI-PE and TPU-HNTs-LiFSI-PE with a thickness of 34 μm exhibit wide electrochemical windows of 4.9 and 5.1 V（vs.Li+/Li） at 60℃,respectively.Reduction in FSI-tends to form more LiF and sulfur compounds at the interface between TPU-HNTs-LiFSI-PE and Li metal anode,thus enhancing the interfacial stability.As a result,cell composed of TPU-HNTs-LiFSI-PE exhibits a smaller increase in interfacial resistance of solid electrolyte interphase（SEI） with a distinct decrease in charge-transfer resistance during cycling.Li|Li symmetric cell with TPU-HNTs-LiFSI-PE could keep its stable overpotential profile for nearly 1300 h with a low hysteresis of approximately39 mV at a current density of 0.1 mA cm-2,while a sudden voltage rise with internal cell impedance-surge signals was observed within 600 h for cell composed of TPU-HNTs-LiTFSI-PE.The initial capacities of NCMITPU-HNTs-LiTFSIPEILi and NCMITPU-HNTs-LiFSI-PEILi cells were 149 and 114 mAh g-1,with capacity retention rates of 83.52% and89.99% after 300 cycles at 0.5 C,respectively.This study provides a valuable guideline for designing flexible SPCE,which shows great application prospect in the practice of ASSLB.
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