Novel gel polymer electrolyte for high-performance lithium-sulfur batteries

The ability to suppress the dissolution of lithium polysulfides in liquid electrolyte (LE) is emerging and scientifically challenging, representing an important endeavor toward successful commercialization of lithium-sulfur (Li-S) batteries. In this context, a common and effective strategy to address this challenge is to replace the LE with a gel polymer electrolyte (GPE). However, the limited ionic conductivity of state-of-the-art GPEs and poor electrode/GPE interfaces greatly restrict their implementation. Herein, we report, for the first time, a facile in-situ synthesis of pentaerythritol tetraacrylate (PETEA)-based GPE with an extremely high ionic conductivity (1.13×10^-2 S cm^-1). Quite intriguingly, even interfaced with a bare sulfur cathode, this GPE rendered the resulting polymer Li-S battery with a low electrode/GPE interfacial resistance, high rate capacity (601.2 mA h g^-1 at 1 C) and improved capacity retention (81.9% after 400 cycles at 0.5 C). These remarkable performances can be ascribed to the immobilization of soluble polysulfides imparted by PETEA-based GPE and the construction of a robust integrated GPE/electrode interface. Notably, due to the tight adhesion between the PETEA-based GPE and electrodes, a high-performance flexible polymer Li-S battery was successfully crafted. This work therefore opens up a convenient, low-cost and effective way to substantially enhance the capability of Li-S batteries, a key step toward capitalizing on GPE for high-performance Li-S batteries.