Heavily heteroatoms doped carbons with tunable microstructure as the iodine hosts for rechargeable zinc-iodine aqueous batteries

Rechargeable zinc-iodine aqueous batteries are promising energy storage technology by virtue of their natural abundance, low costs, and high safety. However, it is still restricted to the sluggish electrochemical reaction kinetics and lack of high-performance host materials. Here, four types of porous carbons including carbon nanosheets, carbon nanoshells, carbon skeletons, and carbon dodecahedrons have been produced with ZIF-8 as the precursor by simply changing the additives. Not only the morphologies but also the specific surface area as well as the pore size distributions of the resulting samples can be well regulated while maintaining a high heteroatomic content, which affords a multifunctional platform to explore the structure-electrochemical performance relationship when serving as the iodine hosts for zinc-iodine aqueous batteries. Moreover, the plentiful of heteroatomic functional groups and inorganic species can shift the weak van der Waals force between hosts and iodine species to strong chemical interaction through halogen bonds. Therefore, the maximum specific capacity can reach 313.6 mAh g−1 (at 0.5 C), good rate capability at 100 C, and long cycle life. Furthermore, the interaction between iodine and host as well as the energy storage mechanism has been explored based on s series of spectral analysis techniques. This work offers the possibility to design high-performance aqueous zinc-based batteries via the optimization of suitable carbon hosts.