Adjusting Li+ Solvation Structures via Dipole–Dipole Interaction to Construct Inorganic‐Rich Interphase for High‐Performance Li Metal Batteries

Abstract

AbstractPractical applications of lithium metal batteries are limited by unstable solid electrolyte interphase (SEI) and uncontrollable dendrite Li deposition. Regulating the solvation structure of Li+ via modifying electrolyte components enables optimizing the structure of the SEI and realizing dendrite‐free Li deposition. In this work, it is found that the ionic–dipole interactions between the electron‐deficient B atoms in lithium oxalyldifluoro borate (LiDFOB) and the O atoms in the DME solvent molecule can weaken the interaction between the DME molecule and Li+, accelerating the desolvation of Li+. On this basis, the ionic–dipole interactions facilitate the entry of abundant anions into the inner solvation sheath of Li+, which promotes the formation of inorganic‐rich SEI. In addition, the interaction between DFOB− and DME molecules reduces the highest occupied molecular orbital energy level of DME molecules in electrolytes, which improves the oxidative stability of the electrolytes system. As a result, the Li||Li cells in LiDFOB‐containing electrolytes exhibit an excellent cyclability of over 1800 h with a low overpotential of 18.2 mV, and the Li||LiFePO4 full cells display a high‐capacity retention of 93.4% after 100 cycles with a high Coulombic efficiency of 99.3%.