Enabling I₃–/I₂ Redox Couple toward High-Voltage Zn-Polyiodide Batteries by the Iodide–π Conjugation Effect

redox couple. Consequently, PIL-tri@GP Zn-polyiodide batteries demonstrate a high output voltage (1.47 V), long cycling (800 cycles), and high-areal-capacity twice that of graphite paper (1.2 V) at a harsh N/P ratio (1). Meanwhile, they exhibited a polarity-switchable characteristic that maintained stable cyclability of 300 cycles when the anode and cathode were reversed every 50 cycles.