Multi-walled carbon nanotube papers as binder-free cathodes for large capacity and reversible non-aqueous Li–O2 batteries†
Multi-walled carbon nanotubes (MWCNTs) were interpenetrated together to form a 3-dimensional porous structure, multi-walled carbon nanotube paper (WCNTP), by a floating catalyst method. The as-synthesized MWCNTP was employed as an air cathode for non-aqueous Li–O2 batteries without the addition of any binder or conductive additives. A huge specific capacity of 34 600 mA h g−1 could be obtained at a current density of 500 mA g−1. 50 cycles of continuous discharge and charge have been achieved with no capacity loss at 250 mA g−1, with a cut-off capacity of 1000 mA h g−1. The reversible formation and decomposition of the discharge product Li2O2 was clearly revealed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). These results suggest the great potential of the binder-free MWCNTPs as air cathodes for Li–O2 batteries with high energy density.