Hierarchical porous soft carbon host for the cathode of an aqueous zinc-iodine battery with ultra-long cycle life

•Porous soft carbon host for iodine loading.•PTCC900 limits the polyiodide dissolution and alleviates the shuttle effects.•50,000 cycles at 5A g−1 with ultra-high capacity retention.•No need to introduce heteroatoms or additional pore formation steps.•High electrical conductivity and hierarchical porous structure at the same time.