Highly Microporous Carbon from Enteromorpha for High-Performance Aqueous Zinc-chalcogen (S, SeS2) Batteries

Graphical Microporous biomass carbon : The Enteromorpha-derived nitrogen-doped highly microporous carbon (HMCs) was prepared by carbonization and activation. Due to the high specific surface area, rich pore structure and nitrogen doping of HMCs, HMCs-3@S/SeS 2 cathode exhibits excellent cycling stability and rate performance in aqueous Zn-chalcogen batteries. Rechargeable aqueous zinc-chalcogen batteries have become a rising star in the energy storage systems due to the high abundance, low cost and high theoretical specific capacity of the chalcogen cathodes (S, Se). However, there are still some challenges in its practical application, such as low utilization of active substances due to the poor conductivity of chalcogen and sizable volume changes during charging/discharging. In this work, for the first time, nitrogen-doped highly microporous biomass-derived carbon (HMCs-3) was synthesized as a sulfur-loaded cathode for aqueous zinc-chalcogen batteries. A high specific surface area (3349.4 m 2 g −1 ) and a wealthy micropore of HMCs-3 provide enough space to load the active substances and allow electrolytes to access reaction sites while well alleviating the volume changes of sulfur during the cycling process. As a cathode for aqueous zinc-chalcogen batteries, HMCs-3@S delivers a high reversible discharge capacity (591 mAh g −1 at 0.1 A g −1 ), an excellent rate capability (477 mAh g −1 at 3 A g −1 ) and good cycling stability (559 mAh g −1 after 100 cycles at 1 A g −1 ). The excellent performance of this biomass-derived carbon holds great promise for practical applications in aqueous zinc-chalcogen batteries.