Multifunctional binder capable of promoting the reaction dynamics of wide temperature operable lithium-sulfur battery

Abstract

Lithium-sulfur battery (Li-S battery) is regarded as one of the most promising next generation energy storage system due to high specific energy and low cost. However, the existing problems including the shuttle effect of lithium polysulfides (LiPSs) and the volume effect of active material during electrochemical process lead to rapid capacity attenuation and low Coulombic efficiency, which finally hinders the practical application of Li-S battery. Therefore, a multifunctional binder is developed in this work to address above issues. In our strategy, a cross-linked binder (named as PLG) is in-situ generated by the hydrogen-bonding interaction between polyacrylamide, locust bean gum and gellan gum, which is conducive to suppress the electrode volume variation by cross-linked network and anchor the LiPSs due to the abundant hydroxyl/amino groups in polymer backbone. Remarkably, the PLG based electrode presents the discharge capacity of 623.4 mAh/g at 0.2 C after 200 cycles, which is almost twice as high as that of PVDF counterpart (342 mAh/g). Most importantly, the cycling performance is demonstrated across a wide temperature range from 0 to 60 °C, high capacity of 516 mAh/g and 440 mAh/g are remained after long-term cycling, respectively. Furthermore, the lithium-ion diffusion influenced by binder is delicately analyzed using cyclic voltammetry at variable speeds and in-situ electrochemical impedance spectroscopy, PLG binder is conducive to improve the reaction kinetic of electrode due to generation of cross-linked structure. This research demonstrates promising performance of multifunctional polysaccharide-based binder for wide temperature operable lithium-sulfur batteries.