Highly flexible transparent substrate-free photoanodes using ZnO nanowires on nickel microfibers

•Breakthrough demonstration of freestanding flexible high-performance photoanodes.•Uniform growth of ZnO nanowires improves photoelectrochemical performance.•ZnO NW/Ni fiber photoanode produces photocurrent density of 1.14 mA/cm2 at 0.4 V vs Ag/AgCl.•Unique morphology provides exceptional stability even after 1000 bending cycles.