Rational design of air-stable and intact anode-electrolyte interface for garnet-type solid-state batteries

Garnet-type solid-state electrolytes are a promising fast lithium-ion conductor due to their high roomtemperature ion conductivity and inherent stability against lithium metal. However, interfacial lithiophobic Li2CO3 makes garnet/Li interfacial ionic contact challenging. The general approach to physically or chemically eliminating Li2CO3 inevitably leads to a Li-deficiency layer at the garnet surface, significantly retarding interfacial ion transport. Contrary to the aforementioned approach, herein we chemically upcycle the Li2CO3 on the garnet surface via the double replacement reaction between Li2CO3 and SiO2. This approach in-situ constructs an air-stable and lithiophilic LixSiOy (LSO) on the garnet surface and averts the Li-deficiency layer formation. The LSO modified symmetric cell displays a low interfacial impedance of 3 omega cm2 and a high critical current density of 1.2 mA cm-2 at 30 0C. This work provides a promising strategy to upcycle interfacial Li2CO3 on the garnet electrolyte.

Automated summary

Garnet-type solid-state electrolytes are considered as promising fast lithium-ion conductors due to their high room temperature ion conductivity and stability against lithium metal. However, the presence of lithiophobic Li2CO3 at the garnet/Li interface poses challenges for ionic contact. In this study, researchers chemically upcycled the Li2CO3 on the garnet surface through a double replacement reaction with SiO2, forming a stable and lithiophilic LixSiOy (LSO) layer that improved interfacial ion transport efficiency.