掺杂LiTFSI的环氧树脂粘结剂填充修复LATP固态电解质表面

Fill and Repair the Surface of LATP Solid Electrolyte Using Epoxy Resin Binder Doped with LiTFSI

摘要: 固态锂离子电池以其高的理论比容量与宽的电化学窗口成为替代传统液态锂离子电池的主要研究方向。NASICON型的LATP作为固态电解质中研究较为广泛的种类，其与锂金属电极间的副反应问题制约着LATP未来的发展。本文通过掺杂LiTFSI的环氧树脂粘结剂表面渗透修复LATP固态电解质表面孔隙，环氧树脂的填充有效减少了Li|LATP界面间的接触面积，延缓了Li|LATP界面间的副反应，LiTFSI的掺杂使环氧树脂粘结剂具有一定的离子导电性，增强了电池的长循环性能。改性后的对称电池在0.1 mA cm⁻²电流密度下循环超过130 h。在Li|LATP界面间加入PEO凝胶缓冲层后，在0.1 mA cm⁻²电流密度下稳定循环超过1800 h，全电池稳定循环200次，容量保持率为89%，库伦效率约为100%。

Abstract: Solid-state lithium-ion batteries, with their high theoretical specific capacity and broad electrochemical window, have become the main research direction for replacing traditional liquid lithium-ion batteries. NASICON-type LATP, as one of the widely studied solid electrolytes, is constrained by side reactions between the LATP and lithium metal electrodes, hindering the future development of LATP. In this paper, surface pore-filling of the LATP solid electrolyte is performed by permeation of an epoxy resin binder doped with lithium salts, where the filling of epoxy resin effectively reduces the contact area between the Li|LATP interface, delaying side reactions at the Li|LATP interface. The addition of lithium salts endows the epoxy resin binder with a certain ionic conductivity, enhancing the battery’s long-cycle performance. The modified symmetric battery cycled for more than 130 h at a current density of 0.1 mA cm⁻². After adding a PEO gel buffer layer at the Li|LATP interface, the cycle exceeded 1800 h at a stable cycle at a current density of 0.1 mA cm⁻², the full battery cycled stably for 200 cycles, with capacity retention of 89% and a coulombic efficiency of about 100%.