V₂O₃ Nanoparticles Confined in High-Conductivity and High-Throughput Carbon Nanofiber Nanohybrids for Advanced Sodium-Ion Capacitors

Electrode materials with high conductivity and high mass transport rate are highly desirable for a variety of electrochemical energy devices but face a grand challenge to be readily prepared yet. Here, we propose the design and preparation of a nanohybrid of V2O3 nanoparticles embedded in a multichannel carbon nanofiber (V2O3@MCNF) network with high conductivity and high mass transport. We demonstrate the V2O3@MCNF shows superior capability for sodium storage with an excellent capacity of 214.3 mA h g–1 even at 5 A g–1, thanks to its high conductivity for electron transfer and facilitated mass transportation endowed by the one-dimensional conductive multichannel fiber structure. Such favorable structures and properties in V2O3@MCNFs enable them to be applied as high-performance anodes of sodium-ion hybrid capacitors (SIHCs), successfully addressing the critical kinetics imbalance between Faradaic anodes and capacitive cathodes for application of SIHCs, which show impressively high energy/power densities along with impressive cycling performance over 10,000 cycles.