Performance-improved Li–O2 battery with Ru nanoparticles supported on binder-free multi-walled carbon nanotube paper as cathode

Abstract

Ru nanoparticles have been deposited onto a multi-walled carbon nanotube paper (Ru@MWCNTP) via a wet chemical method. The resulting catalyst, Ru@MWCNTP has been demonstrated to significantly reduce the charge overpotentials of the Li–O₂ battery at a current density of 500 mA g⁻¹. The reversible formation and decomposition of Li₂O₂ can be revealed by X-ray diffraction (XRD). In the initial 20 cycles of discharge and charge, the Li–O₂ battery with Ru@MWCNTP presents a stable capacity of 5000 mA h g⁻¹ and an almost constant discharge–charge potential, contrasting with the quickly decaying capacity of the bare MWCNTP without the addition of Ru nanoparticles. The combination of the porous networks of the multi-walled carbon nanotubes (MWCNTs), which are beneficial for the facile transport of both electrons and oxygen, and the superior catalytic activity of Ru nanoparticles enables a good cycling performance and rate capability of the Li–O₂ battery.