MnO2@SnO2 core–shell heterostructured nanorods for supercapacitors

A facile, low-cost synthesis of MnO2@SnO2 core–shell heterostructured nanorods with superior supercapacitance is proposed. The synthesis involves sensitizing MnO2 nanorods with an aqueous SnCl2 solution to ensure the formation of a thin, uniform, and complete shell layer. The SnO2 coatings have rough surfaces and their thickness is about 18 nm. The MnO2@SnO2 composites have a specific capacitance of 367.5 F/g at 50 mV/s in 1 M Na2SO4, which is about four and six times of the pure MnO2 nanorods and SnO2 products. Meanwhile, they have 91.3% capacitance retention over 2000 cycles, which is much better than pure MnO2 nanorods. The remarkable performances with a low-cost imply that they have potential for supercapacitors applications.