Sustainable Cow Hair Biocarbon‐Sulfur Cathodes with Enhanced Electrochemical Performance

A sustainable cow hair‐based biocarbon/sulfur composite was prepared via a melt‐diffusion process and used as cathode for lithium–sulfur (Li−S) batteries, exhibiting high capacity, good rate capability, and excellent cyclability. The effect of the activation process during the formation of the biocarbon was deeply analyzed by thermogravimetry, N 2 adsorption, X‐ray photoelectron spectroscopy, scanning and transmission electron microcopy, among others. A correlation between the composition and the surface area with the electrochemical performance was found. The best results were obtained using an activated sample and composite electrode containing 73 wt % sulfur, which present an initial discharge capacity of around 1200 mAh/g and 799 mAh/g after 100 cycles at a current density of 0.1 A/g. Moreover, a specific capacity of ~701 mAh/g was measured at 1 C. The great electrochemical performance of this electrode in Li−S batteries is attributed to the porous carbon structure. Taking into account that hair is one of the major waste produced in the leather sector, this work presents a promising approach to reuse this material by giving it added value through the preparation of carbon/sulfur composites for high‐performance Li−S batteries.