Interface regulation enabling three-dimensional Li1.3Al0.3Ti1.7(PO4)3-reinforced composite solid electrolyte for high-performance lithium batteries

Abstract

Composite solid electrolyte (CSE) consisting of Li+ conductive fillers and polymer matrix has become attractive for high energy-density lithium batteries. Current researches focus on the “ceramic in polymer”-type CSE due to the severe agglomeration of ceramic particles. Consequently, the destroyed percolation network impedes the further improvement in ionic conductivity. In this work, we report a novel structural design of ceramic-enriched CSE consisting of three-dimensional (3D) interconnected Li1.3Al0.3Ti1.7(PO4)3 (LATP), polyvinylidene fluoride (PVDF) and LiN(SO2)2(CF3)2 (LiTFSI). The 3D LATP network is constructed through the surface functionalization of LATP particles by polymethyl methacrylate (PMMA). Owing to the intermolecular interaction between PMMA and PVDF, the incorporation of PMMA-coated LATP (denoted as LATP@PMMA) enables the uniform distribution of ceramic phase and generates interconnected LATP network. Noticeably, such an electrolyte maximizes the utilization of inorganic fillers through the facile treatment of zero-dimensional materials, which is comparable to those 3D template-derived fillers. Furthermore, continuous Li+ conduction pathways through LATP framework and LATP/PVDF interphase are guaranteed by the enhanced affinity of LATP towards PVDF matrix and the intrinsic Li+ complexation capability of PMMA. Remarkable cycling performances of the LiNi0.5Co0.2Mn0.3O2/LATP@PMMA-PVDF/Li batteries confirm the feasibility of 3D ceramic-enriched composite electrolyte in the application of solid-state lithium batteries.