Impact of Li$_{2.9}$B$_{0.9}$S$_{0.1}$O$_{3.1}$ glass additive on the structure and electrical properties of the LATP-based ceramics

TL;DR

This study investigates how adding Li2.9B0.9S0.1O3.1 glass to LATP ceramics improves ionic conductivity and microstructure, aiming to enhance solid electrolyte performance for lithium-ion batteries.

Contribution

It introduces a novel composite approach using LBSO additive to significantly enhance the ionic conductivity of LATP-based ceramics.

Findings

LBSO addition increases ionic conductivity of LATP ceramics.

Optimal sintering at 800°C yields highest conductivity of 1.5 x 10^-4 S/cm.

Microstructure and density correlate with improved electrical properties.

Abstract

The existing solid electrolytes for lithium ion batteries suffer from low total ionic conductivity, which restricts its usefulness for the lithium-ion battery technology. Among them, the NASICON-based materials, such as Li1.3Al0.3Ti1.7(PO4)3 (LATP) exhibit low total ionic conductivity due to highly resistant grain boundary phase. One of the possible approaches to efficiently enhance their total ionic conductivity is the formation of a composite material. Herein, the Li2.9B0.9S0.1O3.1 glass, called LBSO hereafter, was chosen as an additive material to improve the ionic properties of the ceramic Li1.3Al0.3Ti1.7(PO4)3 base material. The properties of this Li1.3Al0.3Ti1.7(PO4)3-xLi2.9B0.9S0.1O3.1 (0 < x < 0.3) system have been studied by means of high temperature X-ray diffractometry (HTXRD), 7Li, 11B, 27Al and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), thermogravimetry (TG), scanning electron microscopy (SEM), impedance spectroscopy (IS) and density methods. We show here that the introduction of the foreign LBSO phase enhances their electric properties. This study reveals several interesting correlations between the apparent density, the microstructure, the composition, the sintering temperature and the ionic conductivity. Moreover, the electrical properties of the composites will be discussed in the terms of the brick-layer model (BLM). The highest value of {\sigma}tot = 1.5 x 10-4 Scm-1 has been obtained for LATP-0.1LBSO material sintered at 800{\deg}C.