Sulfur‐Tuned Advanced Carbons of Novel Properties and Scalable Productivity

Abstract

Sulfur‐tuned advanced carbons (STACs) with high mass loadings of sulfur are synthesized using an environmentally benign and scalable steam‐assisted sulfur insertion (SASI) method. While steam provides the pressure necessary to promote deep and rapid sulfur insertion into a carbon porous structure, a strong affinity between melted sulfur and carbon excludes water from pore penetration. The resulting STACs exhibit sulfur mass loadings up to 85% and the electrical conductivity of the carbon framework is largely preserved. The sulfur penetration can be tuned to fill specific pore sizes, enabling pore‐size‐dependent allocation of sulfur and controllable porosity, while sulfur lines the carbon pore surfaces. A significant amount of sulfur is in the monoclinic γ phase. To demonstrate their energy and environmental applications, the STACs are used as cathode materials in rechargeable aluminum‐sulfur batteries and as adsorption materials for spilled oil removal.

Elucidating Consequences of Selenium Crystallinity on Its Electrochemical Reduction in Aluminum–Selenium Batteries

“…The nascent field of rechargeable aluminum (Al) batteries has generated promising results as a consequence of aluminum’s large theoretical capacity (2980 mA h g –1 ), high abundance, low cost, and inherent safety. , Despite this promise, rechargeable aluminum batteries are currently hindered by a lack of high-capacity cathode materials, which furthermore must be compatible with chloroaluminate electrolytes . Elemental chalcogen electrodes such as sulfur (S) and selenium (Se) have garnered recent interest due to their large theoretical capacities; ,− however, these conversion electrodes typically suffer from slow electrochemical kinetics, large volume changes upon cycling, and poor reversibility due to the formation of electrolyte-soluble reaction intermediates . Sulfur electrodes are highly resistive, necessitating the use of electrodes with high carbon content, which reduces their specific capacity.…”