Zein protein binder coupled with chitosan-derived carbon for polysulphide trapping in Li–S battery

Abstract

For relatively newer developments such as Li–S battery, polysulphide shuttle effect, volume expansion, and low conductivity of sulphur have been the main hurdles in the path towards its commercialisation. To get rid of the polysulphide shuttle effect, we looked at the binder material of the cathode component. An attempt at keeping up with the capacity while making components sustainable led us to explore a protein-based biopolymer, zein. The carbonyl-rich binder helped to glue the components together while the long chain of amino acids aided in preserving the performance. The UV-visible spectroscopy technique verified the adsorption of polysulphides by zein and activated carbon. The carbon host used for this study possessed a high Bruner Emmet Teller (BET) surface area of around 1900 m² g^–1, which helped to load higher amounts of sulphur, as revealed by thermogravimetric analysis. Owing to a porous host, the volume expansion effect could also be buffered to maintain the performance as observed through stability studies. The cycling study of zein binder containing cathode showed an enhanced performance of around 100 mAh g^–1 throughout the 250 cycles compared to the PVDF binder containing cathode.