A Tellurium‐Boosted High‐Areal‐Capacity Zinc‐Sulfur Battery

Abstract

Abstract Aqueous rechargeable zinc‐sulfur (Zn‐S) batteries are a promising, cost‐effective, and high‐capacity energy storage technology. Still, they are challenged by the poor reversibility of S cathodes, sluggish redox kinetics, low S utilization, and unsatisfactory areal capacity. This work develops a facile strategy to achieve an appealing high‐areal‐capacity (above 5 mAh cm−2) Zn‐S battery by molecular‐level regulation between S and high‐electrical‐conductivity tellurium (Te). The incorporation of Te as a dopant allows for manipulation of the Zn‐S electrochemistry, resulting in accelerated redox conversion, and enhanced S utilization. Meanwhile, accompanied by the S‐ZnS conversion, Te is converted to zinc telluride during the discharge process, as revealed by ex‐situ characterizations. This additional redox reaction contributes to the S cathode's total excellent discharge capacity. With this unique cathode structure design, the carbon‐confined TeS cathode (denoted as Te1S7/C) delivers a high reversible capacity of 1335.0 mAh g−1 at 0.1 A g−1 with a mass loading of 4.22 mg cm−2, corresponding to a remarkable areal capacity of 5.64 mAh cm−2. Notably, a hybrid electrolyte design uplifts discharge plateau, reduces overpotential, suppresses Zn dendrites growth, and extends the calendar life of Zn‐Te1S7 batteries. This study provides a rational S cathode structure to realize high‐capacity Zn‐S batteries for practical applications.

Keywords

• areal capacity
• hybrid electrolyte
• hydrogen evolution
• redox kinetics
• tellurium‐sulfur cathode
• zinc‐sulfur battery