Dipole-Dipole Interaction Induced Electrolyte Interfacial Model to Stabilize Antimony Anode for High-Safety Lithium-Ion Batteries

초록

Electrolyte plays a vital role in determining battery performances, while the effect of solvent molecular interaction on electrode performances is not fully understood yet. Herein, we present an unrevealed dipole-dipole interaction to show the mechanism of solvent interaction effect on stabilizing the electrolyte for high electrode performances. As a paradigm, a new nonflammable triethyl phosphate (TEP)-based electrolyte is designed to stabilize the bulk alloying anode (e.g., Sb), where an interfacial model is constructed according to the solvation structure induced by the dipole-dipole interaction between TEP and the essential 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE). We demonstrate that the Li+-solvent-anion complexes derived from different solvation structures exhibit different kinetic and electrochemical properties, contributing to varied Sb anode performances in different electrolytes. As a result, a high lithium storage capacity of 656 mAh g-1, robust rate capacities over 4 A g-1, and a long lifespan of more than 100 cycles are achieved, which are better than those reported before. This work presents a different insight into understanding electrolyte effects on electrode performances and provides a guideline for electrolyte design to stabilize alloying anodes and beyond in metal-ion batteries.

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