Free-standing composite of NaxV2O5•nH2O nanobelts and carbon nanotubes with interwoven architecture for large areal capacity and high-rate capability aqueous zinc ion batteries

Abstract

Aqueous zinc ion batteries (ZIBs) have drawn attractive attention due to low cost and high safety. However, further development and application of the aqueous ZIBs depend on cathode materials with large capacity, high rate and cyclic performances as well as high areal capacity. Herein, free-standing composite (named as NVO⊂CNTs 6:4) of NaxV2O5•nH2O (NVO) nanobelts and carbon nanotubes (CNTs) is fabricated by hydrothermal self-assembly followed vacuum filtration and freeze-drying processes. In virtue of porous and conductive architecture, the free-standing NVO⊂CNTs 6:4 composite exhibits good proton and Zn2+ storage performance. When it is used as a cathode for the aqueous ZIBs, the battery exhibits large areal capacity of 3.03 mAhcm−2 at 3 mAcm−2 and superior high-rate capability of 210.4 mAhg−1 at 30 Ag−1 as well as long-term durability with capacity retention of 92.5% after 2500 cycles. Even at a high mass loading of 12 mgcm−2, the battery can still deliver large capacity of 330.5 mAhg−1 at 2 Ag−1. Our results disclose the NVO-based free-standing composite with high areal capacity, excellent rate and cyclic performances, highlighting its great potential application in high-performance aqueous ZIBs.