Tailoring a multi-system adaptable gel polymer electrolyte for the realization of carbonate ester and ether-based Li-SPAN batteries

Abstract

Sulfurized polyacrylonitrile (SPAN) is considered a prospective replacement cathode for high-energy-density lithium–sulfur batteries. Conventional carbonate electrolytes, which are most widely employed in Li-SPAN batteries, exhibit chemical incompatibility with lithium (Li) metal anodes. In addition, for ether-based electrolytes, Li₂S_n (n ≤ 4) is facile to generate during cycling, leading to the shuttle effect and battery failure. Herein, a multi-system adaptable gel polymer electrolyte (named PFGPE) is innovatively advanced via the in situ copolymerization of hexafluorobutyl acrylate and pentaerythritol tetraacrylate to address these issues. Given the feasibility of our strategy, a C–O– and LiF-rich cathode electrolyte interphase (CEI) was constructed, and the uniform distribution of Li⁺ and reduced parasitic reactions were optimized via a solid electrolyte interphase (SEI) with objective gradient distribution. Rapid transportation of Li⁺ and improved reaction kinetics was achieved through polar groups in PFGPE, which also suppressed the dissolution of lithium polysulfides and reduced the loss of active substances. Thus, the excellent performances of Li-SPAN batteries in both carbonate ester and ether systems are demonstrated for the first time, specifically, a high capacity of 725.1 mA h g⁻¹ was achieved in an ether-based SPAN/PFGPE/Li battery after 600 cycles at 0.2C. Additionally, similar to that of the carbonate ester-based electrolyte, an initial capacity of 1392.8 mA h g⁻¹ was achieved, continuously operating for 200 cycles with a minor capacity fade at 0.1C. Hence, this work provides a promising solution for high-performance Li-SPAN batteries with excellent versatility.