Accelerating the electrochemical kinetics of metal-iodine batteries: progress and prospects

Rechargeable metal-iodine batteries (MIBs) have attracted tremendous attention, due to their merits of high-rate performance, remarkable energy density, and low cost. Nevertheless, the torpid electrochemical kinetics of iodine have encumbered the development of practically implementable MIBs technology. To circumvent these issues, various strategies have been explored and utilized to accelerate the redox kinetics of iodine species. The fundamental tuning of metal iodine redox kinetics is crucial for developing advanced and emerging MIBs. Herein, the intractable obstacles that prevent the practical implementation of MIBs are first summarized. Recent representative works of MIBs are systematically reported and discussed in terms of exploration of micro-and nanostructured iodine hosts, optimization of electrolyte formulas, modification of separators, and construction of functional interlayers. Furthermore, the construction of a catalytic iodine cathode to accelerate the real application of MIBs is proposed.