Valorization of brewer's spent grain via systematic study of KOH activation parameters and its potential application in energy storage

Abstract

Porous carbonaceous materials have gained importance due to their multiple uses in energy storage applications. A cost-effective and promising way to synthesize these materials can be achieved through the KOH activation of carbons from agricultural by-products, by carefully controlling certain characteristics, such as yield and specific surface area. This work explores the synthesis and characterization of activated carbons (ACs) derived from brewery waste production and their potential use as cathode material in lithium-sulfur batteries. The study examines key parameters of the activation process, including pyrolysis temperature, soaking activation time, washing procedures, and mixing methods, to maximize the surface area and porosity of the resulting ACs. Different characterization techniques, such as scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption isotherms, were employed to evaluate the structural and chemical properties of the obtained ACs. As a result, biocarbons with highly competitive surface areas up to 1792 m²/g were achieved and tested as hosts for sulfur impregnation for its application in lithium-sulfur cells.