Freestanding, Hierarchical, and Porous Bilayered NaxV2O5•nH2O/rGO-CNT Composite as High-Performance Cathode Materials for Nonaqueous K-ion Batteries and Aqueous Zinc-ion Batteries

Rational design and convenient preparation of freestanding, hierarchical, and porous composites consisting of three-dimensional (3D) conductive carbon and low-dimension nanostructures with well-defined morphology and direct application as electrodes in rechargeable batteries are challenging. Herein, a freestanding, hierarchical, and porous composite composed of bilayered NaxV2O5·nH2O(NVO) nanobelts, carbon nanotubes (CNTs), and reduced graphene oxide (rGO) with a 3D cross-linked structure is prepared by simple one-pot hydrothermal self-assembly and vacuum filtration. The unique hierarchical nanoarchitecture of the hybrid one-dimensional (1D) (NVO nanobelts) and 3D (rGO/CNT) scaffold provides efficient pathways for ion/electron transportation as well as an elastic medium to buffer large volume change of the bilayered NVO nanobelts during cycling. The materials have excellent electrochemical properties as cathodes in the nonaqueous K-ion batteries (KIBs) and aqueous zinc-ion batteries (AZIBs). In the nonaqu...