Triple Ion–Dipole Regulated Solvation Enables Dendrite-Suppressing High-Temperature Stable Lithium-Ion Batteries

Conventional lithium-ion batteries face a stability limitation above 45 °C due to electrolyte decomposition and irregularly growing lithium dendrites, necessitating advanced electrolytes with enhanced thermal safety and high-temperature performance. Herein, when lithium bis(fluorosulfonyl)imide (LiFSI) in glycerol triacetate (GTA) solvent containing three identical ester groups was combined with LiNO3 additive, a robust semi-enclosed Li+ solvation structure with triple ion-dipole interactions was constructed. Endowed with GTA's long-chain characteristics and ester oxygen atom's high polarity, the solvation structure exhibits superior thermal stability. Density functional theory (DFT) calculations confirm that the Li+-carbonyl interaction has a particularly high binding energy, strengthening Li+ solvation structure stability. This design homogenizes high-temperature lithium deposition to mitigate dendrite growth and inhibits electrolyte-electrode side reactions, significantly improving the thermal stability and safety of LiFePO4-based batteries. Specifically, LiFePO4/Li cells achieve stable operation over 100 cycles at 70 °C with 77.4% capacity retention. This work provides fundamental insights into solvation structure design via multi-ion-dipole interactions and offers a reliable strategy for developing safer, high-performance lithium-ion batteries adaptable to extreme thermal environments.