Coordination Chemistry toward Advanced Zn–I 2 Batteries with Four-Electron I – /I 0 /I + Conversion

Aqueous zinc–iodine (Zn–I2) batteries with four-electron (4e) I–/I0/I+ conversion (4eZIBs) offer high energy density but face significant challenges for application, including the polyiodide shuttle effect and I+ hydrolysis for the I2 cathodes and poor reversibility for the Zn anodes. Here, we report a coordination chemistry strategy to address these issues simultaneously by introducing hexamethylenetetramine (HMTA) as an electrolyte additive. In aqueous electrolytes, HMTA undergoes protonation to form positively charged nitrogen moieties that effectively precipitate the polyiodides and I+ species (ICl2–) to mitigate the polyiodides shuttle and I+ hydrolysis. This strategy enables 4eZIBs to achieve a…

• AR
  Australian Research Council

  Awards: CE230100032, DP220102596, IL230100039, DE230100471