Electrocatalytic Activity of Polyaniline in Magnesium–Sulfur Batteries

Rechargeable magnesium–sulfur (Mg–S) batteries offer the potential for inexpensive energy storage alternatives to other metal-ion batteries for the grid scale and household applications. Despite all economic and resource advantages, Mg–S battery chemistry suffers from a complicated reaction mechanism and extremely slow reaction kinetics. To improve the kinetics, we improvise a new electrode architecture where a conductive polymer is used along with a carbon network. This report will bring an important insight of electrocatalytic activity of polyaniline, on the basis of free-radical coupling and is a completely new concept in Mg–S battery chemistry. By the combined electron spin resonance spectroscopy, X-ray photoelectron spectroscopy, and fluorescence lifetime measurements, we perceived that the polyaniline anchors the S₃^•– species from the electrolyte/catholyte through a free-radical-coupling process and thus promotes the reduction to end-discharged products, via a chemical adduct. The concept of free-radical catalysis in Mg/S batteries will open a new knowledge to enhance the active material utilization in the Mg–S batteries.