Ultra-High Mass-Loading Cathode for Aqueous Zinc-Ion Battery Based on Graphene-Wrapped Aluminum Vanadate Nanobelts.

Rechargeable aqueous zinc-ion batteries (AZIBs) have their unique advantages of cost efficiency, high safety, and environmental friendliness. However, challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+. Here, we report on H11Al2V6O23.2@graphene (HAVO@G) with exceptionally large layer spacing of (001) plane (13.36 Å). The graphene-wrapped structure can keep the structure stable during discharge/charge process, thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte. While used as cathode for AZIBs, HAVO@G electrode delivers ideal rate performance (reversible capacity of 305.4, 276.6, 230.0, 201.7, 180.6 mAh g-1 at current densities between 1 and 10 A g-1). Remarkably, the electrode exhibits excellent and stable cycling stability even at a high loading mass of ~ 15.7 mg cm-2, with an ideal reversible capacity of 131.7 mAh g-1 after 400 cycles at 2 A g-1.