In Situ Construction of a LiF-Enriched Interfacial Modification Layer for Stable All-Solid-State Batteries

All-solid-state batteries (ASSBs), particularly based on sulfide solid-state electrolytes (SSEs), are expected to meet the requirements of high-energy-density energy storage. However, the unstable interface between the ceramic pellets and lithium (Li) metal can induce unconstrained Li-dendrite growth with safety concerns. Herein, we design a carbon fluoride-silver (CFx-Ag) composite to modify the SSEs. As lithium fluoride (LiF) nanocrystals can be in situ formed through electrochemical reactions, this LiF-enriched modification layer with high surface energy can more effectively suppress Li dendrite penetration and interfacial reactions between the SSEs and anode. Remarkably, the all-solid-state symmetric cells using a lithium-boron alloy (LiB) anode can stably work to above 2,500 h under 0.5 mA cm(-2) and 2 mAh cm(-2) at 60 degrees C without shorting. A modified LiB parallel to LiNi0.6Mn0.2Co0.2O2 (NMC622) full cell also demonstrates an improved capacity retention and high Coulombic efficiency (99.9%) over 500 cycles. This work provides an advanced solid-state interface architecture to address Li-dendrite issues of ASSBs.

Automated summary

In this study, a carbon fluoride-silver (CFx-Ag) composite is designed to modify the interface issues of sulfide solid-state batteries (ASSBs). By forming a LiF-enriched modification layer, Li dendrite growth and interface reactions are effectively suppressed, leading to improved stability and cycling performance of the battery.