Millisecond-induced defect chemistry realizes high-rate fiber-shaped zinc-ion battery as a magnetically soft robot

Developing a reliable method for tailoring the defect chemistry of electrode at the atomic scale is of importance for improving battery performance, which has been demonstrated to be rather challenging. Herein, we report a sample and facial quenching method to simultaneously realize metal ions doping and oxygen vacancy generation in reconfiguring the desired defect of electrode materials, by quenching V₂O₅ nanowires in cold NiCl₂ aqueous solution (Ni-V₂O₅ NWs) as an example. Through detailed characterization studies, we confirm that the millisecond-induced defect-engineering modifies the local electronic structures and V coordination environmental of the quenched Ni-V₂O₅ NWs, thus promoting fast charge transfer and providing more storage/adsorption sites for Zn²⁺. Consequently, the quenched Ni-V₂O₅ NWs@CNT fiber (CNT = carbon nanotube) cathode exhibits a high-rate capability (71.2% retention after a 500-times increase in current density), and an ultrahigh stack volumetric energy density of 66.5 mWh cm⁻³, when assembled into a quasi-solid-state fiber-shaped Zn-ion batteries together with Zn NSs@CNT fiber (Zn nanosheets electrodeposited on CNT fiber) as the anode. Finally, we integrate the flexible QFZIB into a magnetically fibrous soft robot to demonstrate its promising potential for providing both energy storage and load-bearing capacities.