Sulfur-based cathodes for aqueous zinc ion batteries

Replacing nonaqueous electrolytes with aqueous ones offers safety, lower toxicity, and better kinetics while reducing costs, though they suffer from low energy density. Sulfur-based materials could potentially overcome this limitation, offering high capacity (1672 mA h g⁻¹). In recent years, aqueous Zn‖S batteries have received significant attention. Herein, this perspective highlights their recent advancements and outlines the challenges they face, such as thermodynamic instability and slow redox kinetics. Various optimization strategies are proposed. An overall scheme focuses on molecular engineering, adsorption-catalytic strategies, and electrolyte chemistry to achieve high-performance aqueous Zn‖S batteries. Finally, the roadmap for high-performance aqueous Zn‖S batteries is provided, which includes improving solid-solid transformations, achieving high energy density and long cycle life, and leveraging machine learning for diversified applications. © 2024 The Royal Society of Chemistry.