Ion-selective gel polymer electrolyte and cathode binder derived from a shared polyether to synergistically mitigate polysulfides shuttling in lithium sulfur batteries

As one kind of the most promising candidates for next-generation batteries, lithium-sulfur (Li-S) batteries with high theoretical energy density are still faced with the severe shuttle effect of polysulfides (PS) and safety issues caused by the flammable liquid electrolytes. To overcome the above challenges, an enhanced ion-selective strategy is proposed by collaboratively crosslinking a polyether containing epoxy groups with negatively charged aminated sodium lignosulfonate (ASL) and polar phytic acid (PA), respectively, to prepare a PS-repelling gel polymer electrolyte (AGPE) and a PS-anchoring cathode binder (PMG-PA) for Li-S batteries. The synergistically suppressed shuttle effect of PS makes the Li-S battery deliver a high capacity of 749.7 mAh g^-1 over 200 cycles at 1 C with a super low capacity decay of 0.11 % per cycle, compared to the poor cycling performance (329.1 mAh g^-1 over 200 cycles with a capacity decay of 0.26 % per cycle) of the conventional liquid electrolyte-based battery using polyvinylidene difluoride as the cathode binder. Furthermore, AGPE confines the liquid electrolyte within the polymer network, while ASL quenches free radicals during potential ignition events, thereby significantly enhancing the battery safety during operation. Therefore, the co-design strategy of ion-selective AGPE and PMG-PA cathode binder derived from a shared polyether offers a new way to mitigate polysulfides shuttling for safe and reliable Li-S batteries.