Development of long lifespan high-energy aqueous organic||iodine rechargeable batteries

Abstract Rechargeable aqueous metal||I 2 electrochemical energy storage systems are a cost-effective alternative to conventional transition-metal-based batteries for grid energy storage. However, the growth of unfavorable metallic deposition and the irreversible formation of electrochemically inactive by-products at the negative electrode during cycling hinder their development. To circumvent these drawbacks, herein we propose 3, 4, 9, 10-perylenetetracarboxylic diimide (PTCDI) as negative electrode active material and a saturated mixed KCl/I 2 aqueous electrolyte solution. The use of these components allows for exploiting two sequential reversible electrochemical reactions in a single cell. Indeed, when they are tested in combination with an active carbon-enveloped I 2 electrode in a glass cell configuration, we report an initial specific discharge capacity of 900 mAh g −1 (electrode mass of iodine only) and an average cell discharge voltage of 1. 25 V at 40 A g −1 and 25 ± 1 °C. Finally, we also report the assembly and testing of a PTCDI|KCl-I 2 |carbon paper multilayer pouch cell prototype with a discharge capacity retention of about 70% after 900 cycles at 80 mA and 25 ± 1 °C.