Sustainable Binder-Driven Four-Electron I – /I 0 /I + Conversion in Metal–Iodine Batteries

Achieving four-electron transfer (I–/I0/I+) in iodine cathodes is crucial for realizing high energy density in metal batteries, but faces limited conversion efficiency and instability of I+ species. Here, we present a binder-centered approach that leverages nucleophilic carboxyl groups in polymer binders to stabilize four-electron iodine redox chemistry confined within the electrode. This design decouples iodine redox chemistry from the electrolyte environment, enabling universal applicability across diverse electrolyte systems. As a result, aqueous Zn–I2 batteries deliver a high specific capacity of 411 mAh g–1 and retain 88% of their capacity after 10,000 cycles at 10 C, while organic Li–I2 batteries achieve…

• NN
  National Natural Science Foundation of China

  Award: 22209124