Approach to Increase the Utilization of Active Material in a High Sulfur-Loaded Cathode for High Areal Capacity Room-Temperature Sodium-Sulfur Batteries

Developing room-temperature sodium-sulfur (RT Na-S) batteries with a high-sulfur-containing cathode and a relatively low amount of electrolyte is the prime factor for implementation of these batteries into the energy storage market. However, it is extremely challenging to achieve stable, long-term cyclability while utilizing a high-sulfur-loaded cathode, since strong adhesion of active material with the current collector should be maintained during charge-discharge. Here, we report manganese dioxide nanoarray-decorated carbon cloth conformally wrapped with sodium-alginate nanofibers (abbreviated as CC@MnO2@Na-alg) as a robust cathode current collector, which not only restricts the gradual dissolution of polysulfides but also offers good adhesion to the active material. To facilitate ion-transport kinetics, a liquid-phase Na2S6 catholyte is used as an active material. At 1C (C = 1672 mA g-1), the catholyte-infiltrated CC@MnO2@Na-alg electrode scaffold, with a high sulfur loading of 3.4 mg cm-2, exhibits a remarkable capacity retention of 94.4% after 1000 cycles. Comprehensive theoretical studies reveal the possible anchoring sites in sodium-alginate for the confinement of the polysulfide species.