Poly(2,3-disulfide-1,4-benzoquinone) as a high-performance cathode for rechargeable aqueous zinc-ion batteries

Abstract

Organic polymer cathodes with flexible backbones and structural diversity have attracted extensive attention in rechargeable aqueous zinc-ion batteries (ZIBs). However, the precursor monomers have limited active sites and large molecular weight, leading to the obtained polymers having limited capacities. Here, we synthesized a novel polymer cathode poly(2,3-disulfide-1,4-benzoquinone) (PSBQ) based on 1,4-benzoquinone and lithium sulfide using the solvothermal method. The PSBQ cathode displays a high discharge capacity of 216.5 mA h g⁻¹ with a capacity retention of 85.2% after 200 cycles at 1 A g⁻¹. The assembled flexible Zn‖PSBQ battery exhibits capacity retention of 90% after 90° and 180° bending. The superior performance is contributed by the polymerization and the flexible molecular backbone of PSBQ as well as the enhanced reactivity and stability of the Zn anode enabled by the 3.0 M ZnSO₄ electrolyte. This work provides a novel strategy for designing high-capacity polymer cathodes in aqueous ZIBs.