Two‐Dimensional Fluorinated Graphene Reinforced Solid Polymer Electrolytes for High‐Performance Solid‐State Lithium Batteries
Two‐Dimensional Fluorinated Graphene Reinforced Solid Polymer Electrolytes for High‐Performance Solid‐State Lithium Batteries
复制标题
高性能固态锂电池用二维氟化石墨烯增强固体聚合物电解质
DOI：
10.1002/aenm.202200967
复制
发表时间：
2022-09
影响因子：
27.8
通讯作者：
Pengbo Zhai;Zhilin Yang;Yi Wei;Xiangxin Guo;Y. Gong
中科院分区：
文献类型：
--
作者：
Pengbo Zhai;Zhilin Yang;Yi Wei;Xiangxin Guo;Y. Gong
固体聚合物电解质（SPE）在固态锂电池的应用中具有很大的前景，但存在机械性能差和电极/电解质界面反应不可控的问题，这限制了其整体电化学性能。在本文中，报告了2D氟化石墨烯增强的PVDF-HFP-LiTFSI（FPH-Li）聚合物电解质的设计以解决这些挑战。均匀分散的氟化石墨烯诱导了独特的晶粒细化效果，这有效地改善了聚合物电解质的机械性能，而不会过度增加聚合物电解质的厚度。聚合物颗粒尺寸的显著减小增强了界面锂离子（Li‐ion）传输并使Li‐ion通量均匀化，从而提高了Li‐ion导电性并促进了Li镀覆/剥离的均匀性。此外，广泛的表征表明，氟化石墨烯参与构建稳定的人工界面，这有效地防止了锂金属阳极和溶剂化分子之间的副反应。因此，使用薄的FPH-Li聚合物电解质（厚度为45 µm）可在Li/Li对称电池中实现长时间的Li电镀/剥离，且过电位较小，并可在1.0 C时实现Li/LiNi0.6Co0.2Mn0.2O2全电池的稳定循环，平均库仑效率高达99.5%。这项工作验证了2D材料在改善聚合物电解质综合性能方面的有效性，并促进了SPE在高性能固态锂电池中的应用。
Solid polymer electrolytes (SPEs) hold a great promise in the application of solid‐state lithium batteries, but suffer from poor mechanical properties and uncontrolled electrode/electrolyte interfacial reaction, which restrict their overall electrochemical performance. Herein, the design of 2D fluorinated graphene‐reinforced PVDF‐HFP‐LiTFSI (FPH‐Li) polymer electrolytes to address these challenges is reported. Uniformly dispersed fluorinated graphene induces a unique grain refinement effect, which effectively improves the mechanical properties without excessively increasing the thickness of the polymer electrolyte. Significant reduction in polymer grain size enhances interfacial lithium ion (Li‐ion) transport and homogenizes Li‐ion flux, thereby improving Li‐ion conductivity and promoting uniform Li plating/stripping. Furthermore, extensive characterizations show that fluorinated graphene is involved in the construction of a stable artificial interface, which effectively prevents the side reactions between the lithium metal anode and solvated molecules. As a result, the use of thin FPH‐Li polymer electrolytes (thickness of ≈45 µm) enables long‐term Li plating/stripping with a small overpotential in Li/Li symmetrical cells and stable cycling of Li/LiNi0.6Co0.2Mn0.2O2 full cells with a high average Coulombic efficiency of 99.5% at 1.0 C. This work verifies the effectiveness of 2D materials in improving the comprehensive properties of polymer electrolytes and promotes the applications of SPEs in high‐performance solid‐state lithium batteries.