LAUSR

The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites, electrochemical instability and insufficient ion conductance. To address these issues, flexible composite polymer electrolyte (CPE) membranes with three dimensional (3D) aramid nanofiber (ANF) frameworks are facilely fabricated by filling polyethylene oxide (PEO)-lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) electrolyte into 3D ANF scaffolds. Because of the unique composite structure design and the continuous ion conduction at the 3D ANF framework/PEO-LiTFSI interfaces, the CPE membranes show higher mechanical strength (10.0 MPa), thermostability, electrochemical stability (4.6 V at 60°C) and ionic conductivity than the pristine PEO-LiTFSI electrolyte. Thus, the CPEs display greatly improved interfacial stability against Li dendrites (>1000 h at 30°C under 0.10 mA cm −2 ), compared with the pristine electrolyte (short circuit in 13 h). The CPE-based all-solid-state LiFePO 4 /Li cells also exhibit superior cycling performance (e.g., 130 mA h g −1 with 93% retention after 100 cycles at 0.4 C) than the ANF-free cells (e.g., 82 mA h g −1 with 66% retention). This work offers a simple and effective way to achieve high-performance composite electrolyte membranes with 3D nanofiller framework for promising solid-state Li metal battery applications. 聚合物电解质在锂金属电池中的应用受限于锂枝晶生长、 电化学不稳定性及较低的离子电导率. 为解决这些问题, 本文通过向三维多孔芳纶纳米纤维(ANF)中填充聚环氧乙烷(PEO)-双三氟甲基磺酰亚胺锂(LiTFSI)电解质, 制备了基于三维芳纶纳米纤维网络骨架的柔性ANF/PEO-LiTFSI复合电解质薄膜. 由于其独特的构造及离子在三维ANF/PEO-LiTFSI界面中的连续输运, 该复合电解质膜具有比PEO-LiTFSI电解质膜更高的力学强度(10.0 MPa)、 热稳定性、 电化学稳定性(60°C下达4.6 V)和离子电导率, 以及较强的抑制锂枝晶能力. 基于该复合电解质的固态LiFePO 4 /Li电池表现出优异的循环性能(在0.4 C下充放电百次后的容量达130 mA h g −1 、 保持率为93%). 该研究提供了一种基于三维骨架设计和制备高性能电解质的有效方法, 有望应用于固态锂金属电池.