Regulating Interface Dipole Interaction between Ethers and Active Species toward Highly Stable Li‐SPAN Batteries

Abstract

Sulfurized polyacrylonitrile (SPAN) is recognized as a promising organic cathode for long‐lifespan lithium metal batteries. Nevertheless, the irreversible cleavage/formation of multiple sulfur‐sulfur (S‐S) bonds of SPAN within conventional ether‐based electrolytes results in loss of active S species, severe capacity fading and shuttle effects. Herein, we propose a new electrolyte based on dipropyl ether (PE) solvent for Li‐SPAN batteries. Benefiting from the particular chain‐coordination structure and weak dipole interactions with Li+ and active species, the resulting electrolyte not only achieves low desolvation energy barrier and high Li+ transference number, but also displays stable electrolyte‐electrode interface (EEI). Consequently, the full cells utilizing this electrolyte exhibit good cyclability, outstanding capacity retention and superior extreme‐temperature (‐50°C to 50 °C) performance. Furthermore, the Ah‐scale pouch cell with lean electrolyte (2.5 g Ah‐1) achieves record cycle stability with 96.5% capacity retention after 75 cycles, which deliver an initial specific energy density of 150 Wh kg‐1 (based on the weight of the entire cell). Impressively, this strategy demonstrates universality in a series of organic electrodes employing with PE‐based electrolytes. This work highlights the strategy for modulating the dipole interaction at EEI for long‐lifespan Li‐organic batteries at extreme conditions.