A new role for chlorine: Uncovering anion redox in solid-state battery cathodes

As demand grows for safer and more capable rechargeable batteries, scientists are looking beyond the familiar metal-centered chemistry of conventional cathodes. A promising route is to draw additional charge from anions—the negatively charged atoms in a material—rather than relying on transition metals alone. Oxygen and sulfur have attracted substantial attention in this area. Whether chlorine can play a comparable role in chloride-based battery cathodes has been less clear.