Growth of 3D SnO2 nanosheets on carbon cloth as a binder-free electrode for supercapacitors

Three-dimensional (3D) lamellar SnO2 is grown on a carbon cloth (CC) substrate (denoted as 3D lamellar SnO2/CC) through hydrothermal reactions and subsequent thermal treatments. The resulting 3D lamellar SnO2/CC can be directly used as an electrode in supercapacitors without the necessity for addition of either binder or conductive species, and achieves a specific capacitance as high as 247 F g(-1) at a current density of 1 A g(-1) within a potential window ranging from -0.6 to 0.3 V because of the unique porous structure accessible to electrolyte ions. In order to match the capacitive behaviors of 3D lamellar SnO2/CC in the two-electrode systems, reduced graphene oxide/carbon cloth (rGO/CC) is prepared by starting from GO. The rGO/CC and 3D lamellar SnO2/CC are respectively used as positive and negative electrodes to assemble an asymmetric supercapacitor. The device exhibits not only an excellent cycle stability (76.9% after 10 000 cycles at 3 A g(-1)), but also high energy density of 22.8 W h kg(-1) at a power density of 850 W kg(-1) under a cell voltage of 1.7 V. Moreover, the as-fabricated supercapacitor has green and environmentally friendly features because an aqueous neutral electrolyte is employed in it.