Enhancing interfacial stability in lithium orthosilicate/polymer blended novel hybrid solid-state electrolytes for all-solid-state lithium metal batteries

Abstract

Hybrid solid-state electrolyte (HSSE) is a key component for the advancement of all-solid-state lithium metal batteries. The key challenges with the existing HSSEs are to ensure high ionic conductivity, activate dead inorganic/organic interface, and stimulate interfacial stability with electrodes. In this study, a novel HSSE is fabricated by integration of appropriately engineered end-of-life photovoltaic recycled high purity silicon derived nano size inorganic lithium orthosilicate and poly (vinylidene fluoride-co-hexafluoropropylene) polymer matrix through entrapping ionic liquid electrolytes. The obtained lithium orthosilicate-polymer blended HSSE is self-standing, soft, and flexible which delivers a low activation energy, leading a high ionic conductivity of 4.4 × 10−4 Scm−1. A critical lithium plating/stripping behaviour shows improved interfacial stability (both inorganic/organic interface and interfaces of HSSE/electrodes) under different current densities (0.05 mA cm−2 to 0.13 mA cm−2) when a drop of ionic liquid electrolyte is added, permitting cycling of an all-solid-state full cell (Li/HSSE/LiFePO4) at room temperature with high capacity (132 mAh g−1), stable cycle life and high Coulombic efficiency (initial ∼98 %; subsequent >99.5 %). Shaping the interfaces between inorganic/organic phases in the HSSE as well as the interfaces between electrodes/HSSE appears to be a workable path towards constructing very effective HSSE for the advancement of all-solid-state lithium metal batteries.