Ultrafast hetero-assembly of monolithic interwoven V₂O₅ nanobelts/carbon nanotubes architectures for high-energy alkali-ion batteries

Monolithic interwoven composite of V₂O₅ nanobelts and carbon nanotubes (designated as VNTs⊂CNTs-40) is prepared via one-pot hydrothermal synthesis and subsequent vacuum filtration. The strong synergistic effect between versatile CNTs and in situ produced V₂O₅ nanobelts in hydrothermal process leads to the formation of 3D interwoven mesh intermediate with relatively loose and well-reticulated channels which facilitate mass transfer in ultrafast hetero-assembly (∼30s) of film-like monolithic VNTs⊂CNTs-40 composite during vacuum filtration. The interconnected CNTs network and interstitial porous channels in the monolithic VNTs⊂CNTs-40 composite not only improve charge transport during the redox reactions of the active materials, but also serve as a robust and flexible buffer to accommodate the volume change during repetitive ion insertion/extraction. In the evaluation of binder-free cathodes in alkali-ion batteries, the monolithic VNTs⊂CNTs-40 composite exhibits outstanding alkali-ion storage properties such as high initial capacity (215.2/295.8 mAhg⁻¹ for SIBs/LIBs at a current density of 200 mAg⁻¹), high-rate capability (137.8/156.2 mAhg⁻¹ for SIBs/LIBs at a current density of 800/2000 mAg⁻¹), and superior cycling stability (167/223.5 mAhg⁻¹ for SIBs/LIBs at a current density of 200 mAg⁻¹ after 200 cycles). The monolithic VNTs⊂CNTs-40 composite has large potential in high-performance alkali-ion batteries.