High-Capacity Intercalation-Based Anodes for Solid-State Fluoride-Ion Batteries Enabled by the Substitution of Conductive Carbon by Metallic Copper

Fluoride-ion batteries are a promising battery technology to achieve high energy densities exceeding those of traditional lithium-ion batteries. Reports on intercalation-based electrode materials for fluoride-ion batteries have mostly focused on cathode materials, while only a few intercalation-based anode materials have been reported. Their performance was heavily affected by carbon-based reductive side reactions, limiting reversibility and introducing high overpotentials. In this study, we present the successful substitution of carbon by metallic copper in solid-state FIBs, enabling the use of La$_2$NiO$_3$F$_2$, Pr$_2$NiO$_3$F$_2$, Sr$_2$TiO$_3$F$_2$, and Sr$_3$Ti$_2$O$_5$F$_4$ as intercalation-based anode materials by avoiding parasitic side reactions associated with the conductive carbon additive.