All‐Climate Energy‐Dense Cascade Aqueous Zn‐I 2 Batteries Enabled by a Polycationic Hydrogel Electrolyte

based on the mass of iodine, demonstrating exceptional long-term cycling stability over a wide temperature range from -50 to 50 °C. This study offers valuable insights into the rational design of electrolytes for high-energy aqueous batteries, specifically tailored for wide-temperature operation.