Robust method for uniform coating of carbon nanotubes with V₂O₅ for next-generation transparent electrodes and Li-ion batteries

Composites comprising vanadium-pentoxide (V2O5) and single-walled carbon nanotubes (SWCNTs) are promising components for emerging applications in optoelectronics, solar cells, chemical and electrochemical sensors, etc. We propose a novel, simple, and facile approach for SWCNT covering with V2O5 by spin coating under ambient conditions. With the hydrolysis-polycondensation of the precursor (vanadyl triisopropoxide) directly on the surface of SWCNTs, the nm-thick layer of oxide is amorphous with a work function of 4.8 eV. The material recrystallizes after thermal treatment at 600 degrees C, achieving the work function of 5.8 eV. The key advantages of the method are that the obtained coating is uniform with a tunable thickness and does not require vacuuming or heating during processing. We demonstrate the groundbreaking results for two V2O5/SWCNT applications: transparent electrode and cathode for Li-ion batteries. As a transparent electrode, the composite shows stable sheet resistance of 160 U sq(-1) at a 90% transmittance (550 nm) - the best performance reported for SWCNTs doped by metal oxides. As a cathode material, the obtained specific capacity (330 mA h g(-1)) is the highest among all the other V2O5/SWCNT cathodes reported so far. This approach opens new horizons for the creation of the next generation of metal oxide composites for various applications, including optoelectronics and electrochemistry.