High‐Energy Density Aqueous Alkali/Acid Hybrid Zn–S Battery

Abstract Aqueous zinc‐based batteries with high energy density are highly sought after to satisfy the increasing demands on the electrochemical energy device thanks to the advantages of high safety, low cost, and fast kinetics. In this work, a high‐performance hybrid Zn–S battery (h‐ZnSB) is reported by coupling an alkali Zn anode with an acidic sulfur electrode. To this end, atomic Zn–N₄ dispersed on nitrogen‐doped hollow porous carbon (Zn–NHPC) is developed as the host of sulfur that enhances efficiency due to the higher affinity of Zn–N₄ to CuS than N‐doped graphene, which can reduce the vulcanization reaction barrier that is too high on N‐doped graphene. The hybrid Zn–S battery shows desired electrochemical properties, including a high open‐circuit voltage of 1.81 V, high specific capacities of 2250 mAh g⁻¹ at 1 A g⁻¹ and 1500 mAh g⁻¹ at 10 A g⁻¹, as well as a high energy density of 2372 Wh kg⁻¹ at 10 A g⁻¹ based on the total mass of S/C composites. The present work may provide a promising route for the development of high‐energy and high‐safety aqueous batteries.