Structural Investigations of Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics by Solid State NMR

S V Pershina,S G Vlasova,Y V Baklanova,M Y Dzuba

doi:10.1088/1742-6596/1347/1/012054

Abstract

NASICON-type conductors based on LiGe2(PO4)3 are very promising lithium-conducting electrolytes for all-solid-state lithium-ion and lithium batteries. Al-doped LiGe2(PO4)3 solid electrolytes possessed higher conductivity (∼10-4 S/cm at room temperature) and stability versus metallic Li. In this paper, we present the structure study of Li1.5Al0.5Ge1.5(PO4)3 compound. Fast lithium-ion conductor Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte have been obtained through glass crystallization at 820 °C during 8 h. Structural positions occupied by atoms have been examined by solid state nuclear magnetic resonance experiments. 6Li, 7Li, 27Al и 31P NMR measurements have been performed at room temperature.

Highlights

All-solid-state lithium batteries using a solid electrolyte have long-life, safety, excellent rate capability, as well as high voltage and capacity, so they are considered as next-generation power sources [1,2,3]
It should be noted that crystallization of a glass corresponding to the formula Li1.5Al0.5Ge1.5(PO4)3 is the most viable method of obtaining a high-conductivity LAGP electrolyte compared to conventional solid-state and sol-gel methods [6,7,8]
We focused on the structural aspects of this type of compound using nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) at room temperature

Summary

Introduction

All-solid-state lithium batteries using a solid electrolyte have long-life, safety, excellent rate capability, as well as high voltage and capacity, so they are considered as next-generation power sources [1,2,3]. Solid state lithium ion conductors for these applications must be resistant to the aggressive Li, have high lithium ion conductivity at room temperature (> 10-4 S cm-1) and thermal stability, and dense microstructure [4]. It should be noted that crystallization of a glass corresponding to the formula Li1.5Al0.5Ge1.5(PO4) is the most viable method of obtaining a high-conductivity LAGP electrolyte compared to conventional solid-state and sol-gel methods [6,7,8]. The framework of NASICON-type materials can be described as a covalent skeleton M2(PO4) with corner-sharing MO6 octahedra and PO4 tetrahedra which form a three-dimensional (3D) network [1, 4, 5].

Published under licence by IOP Publishing Ltd

Conclusions