Lithium-Ion: Electrolyte

In Situ Li2CO3 Conversion in Solid State Batteries For Improved Interfacial Contact Li-intercalated ceramics, such as LLZTO, often spontaneously form a layer of inactive Li2CO3 upon contact with moisture or CO2, hindering kinetics in cycling. Conventional Li2CO3 removal methods usually involve high temperature or acid-based treatments, which can often damage the underlying ceramic LLZTO electrolyte. Researchers at Tianjin University have developed a low-temperature decarbonization–fluorination strategy to address this issue. By reacting in situ Li2CO3 with LiPF6 at 60°C, they successfully construct ultrastable, LiF-rich interphases throughout the cell. Notably, this fluorination strategy is capable of removing a significant fraction of Li2CO3 across all interfaces, even within grain boundaries. The fluorination of all interfaces also suppresses parasitic reactions while reducing the interface resistance, eliminating gas evolution within the cycling window of up to 4.5V, and demonstrating a cycling stability of up to 7,000 h.

Li2CO3 is a common Li-battery degradation product that inhibits cell cycling. The in-situ conversion of Li2CO3 to LiF-rich regions creates a protective interphase with stable electrochemical cycling.

Source: Guo, Pan, Yi, Chi, Yin, Geng, Yin, Zhan, Zhao, Jin, Fang, He, Kang, Wu, Yang

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