Metal–iodine batteries: achievements, challenges, and future

Abstract

Metal–iodine batteries (MIBs) are becoming increasingly popular due to their intrinsic advantages, such as a limited number of reaction intermediates, high electrochemical reversibility, eco-friendliness, safety, and manageable cost. This review details past attempts and breakthroughs in developing iodine cathode-based (rechargeable) metal battery technology, to arrive at a comprehensive discussion and analysis of the battery's working mechanisms and fundamental challenges. Especially, the realization of available rechargeable MIBs relies heavily on the joint action of the battery components. We therefore cover here the progress starting from electrodes, electrolytes, and separator/interlayer requirements to introduce various types of MIBs and finally a critical analysis of the status quo, allowing us to gain insight into the roadblocks that still exist in MIBs. Also, we collect and compare the electrochemical performance of MIBs by category with listing their actual active material loading species and cell fabrication parameters. Finally, we conclude with recommendations for future strategies to leverage current advances in battery engineering, characteristics, and computational designs, all of which enable MIBs to reach their full potential in the energy age ultimately.