Eucommia leaf residue-derived hierarchical porous carbon by KCl and CaCl2 Co-auxiliary activation for lithium sulfur batteries

Lithium sulfur batteries are listed among the most prospective energy storage devices because of its theoretical specific capacity as high as 1675 mA h/g. However, the actual practice of lithium sulfur batteries meets two major challenges of low utilization of sulfur along with polysulfides shuttling. In this work, a hierarchical porous structure carbon (ECKCa-11) from Eucommia leaf residue-derived as raw materials is manufactured by the co-auxiliary activation of KCl and CaCl2 with a low dosage of KOH. ECKCa-11 possesses reasonable channel distribution with 1724.38 m2/g as specific surface area and nitrogen-containing functional groups, which can chemically “anchor” the lithium polysulfides by LiN interplay. Furthermore, a possible co-auxiliary activation mechanism is proposed by analyzing the surface morphology and the information of specific surface and aperture size distribution of the ECKCa-11 at different temperatures from 500 °C to 900 °C. The ECKCa-11/S cathode offers excellent electrochemical performances, delivering an initial discharge specific capacity of 1336.0 mA h/g at 0.1C in lithium sulfur batteries. This work prepares hierarchical porous carbon from invalid biomass by co-auxiliary activation, reducing the amount of KOH used, preventing equipment corrosion, and mitigating environmental pollution.