Rechargeable Lithium-Iodine Batteries with Iodine/Nanoporous Carbon Cathode

Abstract

Rechargeable Li-iodine batteries\nare attractive electrochemical energy storage systems because iodine\ncathode provides the possibility of high energy density, wide abundance\nand low cost. However, the safety risk caused by low thermostability\nof iodine and the self-discharge reaction due to high solvency of\niodine in aprotic solvent are target issues to be considered. Herein,\nwe designed a room-temperature “solution-adsorption”\nmethod to prepare a thermostable iodine–carbon cathode by utilizing\nthe strong adsorption of nanoporous carbon. Meanwhile, Li-iodine batteries\nconstructed by the as-prepared cathode and ether-based electrolyte\nwith the addition of LiNO₃ showed negligible self-discharge\nreaction, high rate and long cycling performance. The reversible reactions\nof I₂/LiI₃ and LiI₃/LiI in Li-iodine\nbatteries were also proved with in situ Raman measurement. For the\ndemonstration of application, soft-package batteries with Al-plastic\nfilm were assembled, displaying energy densities of 475 Wh/kg by mass\nof Li and iodine, and 136 Wh/kg by total mass of the battery. The\nuse of nanoporous carbon to adsorb iodine at room-temperature represents\na new and promising direction for realizing high-performance cathode\nfor rechargeable Li-iodine batteries.