Unlocking Sluggish Processes of Oxygen Reduction Reaction and Charge Release for High-performance Air-rechargeable Aqueous Zinc-ion Batteries

Air-rechargeable aqueous zinc-ion batteries (ARAZIBs) can capture the chemical energy of O2 in air for self-charging. However, the sluggish air-charging process prevents the further development of ARAZIBs. Herein, based on the multi-scale (geometry/crystal/electronic) structure regulation of V2O5, we construct the heterostructure of nano-size amorphous HVO (H2O-intercalated V2O5) and 2D graphene on carbon paper as the self-supporting HVO@G/CP electrode. The unique geometric-structure endows HVO@G/CP with sufficient accessible active-sites for oxygen-reduction-reaction (ORR). Meanwhile, the changes of crystal/electronic structure caused by H2O-intercalation significantly boost ORR and charge (electron/Zn2+) release of HVO@G/CP during air-charging process. As a result, HVO@G/CP shows an ultrafast air-charging speed, outperforming other reported electrodes for ARAZIBs. Particularly, it delivers an ultrahigh specific capacity of 227.1 and 412.6 mAh g−1 at 0.1 A g−1 after the air-charging of 0.5 h and 6 h. An unprecedented discharge-capacity of 17006 mAh g−1at 0.01 A g−1 can be achieved in the open-air Zn//HVO@G/CP battery. Its practical application is also verified in a wide temperature range (−20℃ − 60℃). Moreover, we firstly reveal that the 3dxy state in V t2g electronic-orbit has a significant impact on the air-charging process of vanadium oxides. Especially, our multi-scale structure regulation, which does not rely on any additional additives or energy stimulation, successfully unlock the sluggish air-charging process, opening the door of ARAZIBs towards practical applications.