Robust Method for V2o5 Coating of Carbon Nanotubes for Next-Generation Transparent Electrodes and Li-Ion Batteries

Abstract

Composites comprising vanadium-pentoxide (V2O5) coating 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 coating with V2O5 by spinning under ambient conditions. With the hydrolysis-polycondensation mechanism of V2O5 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. After 600⁰C heating the material recrystallizes, achieving the work function of 5.8 eV. The key advantages of the method: the obtained coating is uniform with a tunable thickness and it does not require vacuuming or heating during the 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 Ω/sq at a 90% transmittance (550 nm) – the best performance for SWCNTs doped by metal oxides. As a cathode material, the obtained specific capacity (330 mAh/g) is the highest among all the other V2O5/SWCNT cathodes reported so far. These results open new horizons for the next generation of V2O5 composites for various applications, including optoelectronics and electrochemistry.

Keywords: Li-ion battery, transparent conductor, composite material, V2O5, SWCNT