Lithium 2‐trifluoromethyl‐4,5‐dicyanoimidazole (LiTDI) as an Alternative Salt for Aqueous Li‐Ion Batteries

LiTDI is explored as an alternative salt for aqueous lithium-ion batteries. Unlike the widely studied LiTFSI, LiTDI reaches saturation at ≈4 m, leaving a significant amount of free water. Nevertheless, it exhibits promising electrochemical properties, including high ionic conductivity (12 mS cm⁻¹) and a stability window exceeding 2.4 V at just 1 m.

Water-in-salt batteries have emerged as promising candidates for electrochemical storage systems, due to their enhanced safety and low cost compared to conventional Li-ion batteries. However, to date, they relied on very high salt concentrations (mostly LiTFSI salt), meaning that they remain an expensive solution for storage application. LiTDI has previously been reported to act as a water scavenger agent in organic-based electrolyte. Herein, a comprehensive investigation of LiTDI as a potential alternative salt for aqueous batteries is conducted. Although LiTDI exhibits lower electrochemical performance compared to LiTFSI, it enables high ionic conductivity at lower concentrations showing good ability for aqueous battery. Furthermore, it sustains an electrochemical stability window of ≈2.5 V, indicating its potential as a more cost-effective option for aqueous-based high-voltage electrolyte formulations.

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