Anion-Regulated Sulfur Conversion in High-Content Carbon Layer Confined Sulfur Cathode Maximizes Voltage and Rate Capability of K-S Batteries.

Potassium-sulfur (K-S) batteries have attracted attention in large-scale energy storage systems. Small-molecule/covalent sulfur (SMCS) can help to avoid the shuttle effect of polysulfide ions via solid-solid sulfur conversion. However, the content of SMCS is relatively low (≤40%), and solid-solid reactions cause sluggish kinetics and low discharge potentials.