Nonflammable PVDF-based gel polymer electrolytes modified by dimethyl methylphosphate for wide temperature range,long cycle-life and high-safety lithium metal batteries  

甲基膦酸二甲酯改性的不易燃PVDF基凝胶聚合物电解质用于宽温域、长循环寿命和高安全性锂金属电池

作　　者：Yuanjun Zhao Xinyu Da Yanyang Qin Xin Jia Xuetian Deng Shujiang Ding Junqiao Xiong Qiang Rong Xiangpeng Kong Guoxin Gao 赵媛君;答欣宇;秦棪阳;贾鑫;邓雪甜;丁书江;熊俊俏;荣强;孔祥鹏;高国新

机构地区：[1]Xi’an Key Laboratory of Sustainable Energy Materials Chemistry,School of Chemistry,Xi’an Jiaotong University,Xi’an 710049,China [2]Hunan Desay Battery Co.Ltd.,Changsha 410203,China

出　　处：《Science China Materials》2024年第12期3994-4004,共11页中国科学（材料科学）（英文版）

基　　金：supported by the National Natural Science Foundation of China(52273081);the Natural Science Foundation of Shaanxi Province(2019JM-175,and 2021GXLH-Z-075);the Key Laboratory Construction Program of Xi’an Municipal Bureau of Science and Technology(201805056ZD7CG40);the Fundamental Research Funds for the Central Universities。

摘　　要：Gel polymer electrolytes(GPEs)has been considered as a promising candidate for the development of lithium metal batteries(LMBs)with high energy density and high safety,yet most reported GPEs is flammable,making the LMBs still facing great safety hazards.Herein,we used dimethyl methylphosphate(DMMP)as the functional flame retardant and plasticizer for poly(vinylidene fluoride)(PVDF)matrix to develop a novel nonflammable PVDF-DMMP GPEs for LMBs.The DMMP not only highly enhances the flame resistance of PVDF-DMMP GPEs,the efficient dissociation of lithium salt and the rapid transport of lithium ions,but also helps to form stable and robust CEI/SEI layers.As a result,the ultrathin PVDF-DMMP GPEs(∼20µm)present superb flame resistance,high ionic conductivity(1.34×10^(−3) S cm^(−1) at 30℃),fast lithium ion transport(t_(Li^(+))=0.59at 30℃),high electrochemical stability voltage window(over 4 V)at 30–80℃ and uniform lithium deposition.When used in Li∥Li symmetric cells,Li∥LiFePO_(4)(LFP)and Li∥LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) full cells,the nonflammable PVDF-DMMP GPEs could endow these cells with long-term cycle stability,high rate capability,wide-temperature operation ranges(from−20 to 80℃)and high safety simultaneously.Even when suffering from harsh deconstructive tests,the Li∣PVDF-DMMP GPEs∣LFP pouch cells still work normally without any safety hazards.The actual energy density of the packed pouch cell is as high as 508 Wh kg^(−1).Therefore,our work can provide a promising strategy for the design of high safety and high-energy-density LMBs.凝胶聚合物电解质(GPEs)被认为是开发具有高能量密度和高安全性的锂金属电池(LMBs)的有希望的候选材料,然而大多数报道的GPEs是易燃的,使得LMBs仍然面临巨大的安全风险.在这里,我们使用甲基膦酸二甲酯(DMMP)作为功能性阻燃剂和增塑剂,用于聚偏二氟乙烯(PVDF)基质,开发了一种新型的不易燃PVDF-DMMP GPEs用于LMBs.这种DMMP不仅极大地增强了PVDF-DMMP GPEs的阻燃性,还有效提高了锂盐的解离效率和锂离子的快速传输,同时还有助于形成稳定且坚固的CEI/SEI层.因此,超薄的PVDF-DMMP GPEs(约20微米)展现出卓越的阻燃性、高离子导电性(在30℃下为1.34×10^(−3) S cm^(−1))、快速的锂离子迁移(在30℃下t_(Li^(+))=0.59)、在30–80℃下具有宽的电化学稳定性电压窗口(超过4 V)以及均匀的锂沉积.当用于Li∥Li对称电池、Li∥LiFePO_(4)(LFP)和Li∥LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)全电池时,不易燃的PVDF-DMMP GPEs能够使这些电池同时具有长期循环稳定性、高倍率性能、宽温度工作范围(从−20到80℃)和高安全性.即使在遭受严苛的破坏性测试时,Li∣PVDF-DMMP GPEs∣LFP软包电池仍然正常工作,没有任何安全风险.实际的软包电池能量密度高达508 Wh kg^(−1).因此,我们的工作可以为设计高安全性和高能量密度的LMBs提供新的策略.

关 键 词：lithium metal batteries gel polymer electrolyte flame resistance PVDF 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]