Solvation Structure Modulating via Dipole-Dipole Interactions for High-Rate Lithium Metal Batteries Exceeding 400 Wh kg-1

Abstract

Electrolyte engineering is a key strategy to enhance the performance of high-voltage lithium-metal battery (LMB), with localized high-concentration electrolytes (LHCEs) emerging as a promising approach. However, the role of the diluent and its impact on the solvation structure remain unclear. In this study, we demonstrate that the dipole moment of the diluent is crucial for regulating diluent-solvent interactions. By modulating the dipole-dipole interactions between diluent and solvent, the coordination of solvents with Li⁺ has been successfully weakened, promoting the formation of a micelle-like electrolyte with anion-derived solvation. More importantly, the reduced desolvation energy barrier facilitates Li⁺ migration and improves the electrolyte's high-rate performance. The electrolyte achieved remarkable stability for 1500 cycles in a Li||NCM811 cell at 10C with 76% capacity retention and a Coulombic efficiency (CE) of 99.0% in a Li||Cu cell. A prototype pouch cell (3.15 Ah) exhibits a high energy density of 403 Wh kg⁻¹ with a lean electrolyte loading of only 1.9 g Ah⁻¹. These findings provide critical insights into solvent-diluent interactions, advancing the development of fast-charging, high-voltage LMBs.