Iron-Regulated D-Band Center in Fe-V2O5-n/rGO Heterostructures Enables Ultralong-Cycling Zinc-Iodine Batteries via Optimal Iodine Adsorption-Desorption Dynamics
The intrinsically low electrical conductivity of elemental iodine and its slow redox kinetics represent two significant obstacles that hinder the commercialization of aqueous zinc-iodine batteries. These challenges can be addressed by modulating the adsorption-desorption equilibrium of iodide ions in the active material. This study presented a synergistic strategy of “Electronic Modulation” and “Phase Transition Engineering” to optimize the catalytic adsorption-desorption dynamics. A dual-designed Fe ions doped VO 2- x heterostructure anchored on reduced graphene oxide (Fe-VO 2- x /rGO) is demonstrated to synchronously adjust iodine adsorption and boost redox kinetics. The Fe-induced electronic structure modulation elevated the d-band center of vanadium, creating catalytic sites to promote the desorption of iodide ions and facilitate their diffusion. Concurrently, the phase transition from VO 2- x to V 2 O 5- n within the heterostructure establishes a 3D conductive network, synergizing with rGO to ensure rapid ion/electron transport. This “adsorption-catalysis-transport” collaborative mechanism enabled the Fe-VO 2- x /rGO cathode to achieve an ultrahigh capacity retention of 81.48% after 60,000 cycles at 20 A g −1 , surpassing state-of-the-art zinc-iodine systems. The work provides a paradigm for manipulating interfacial dynamics through electronic and crystallographic dual regulation in conversion-type batteries.
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