Facile synthesis of porous SnO2 film grown on Ni foam applied for high-performance supercapacitors

• The porous 3D SnO2/Ni composite foam was successfully synthesized through a facile method.
• The capacitive properties of composite foam as function of pore size of SnO2 was investigated.
• Porous SnO2@Ni composite foam exhibited high capacitive properties.

Here, a novel three dimensional Ni foam-supported porous SnO2 film (SnO2/Ni composite foam) was successfully synthesized by the simple hydrothermal method. The porous SnO2 film had closely coated on the backbones of Ni foam without assistant of surfactant at mild conditions. At the same time, the pore size of SnO2/Ni composite foam was easily controlled by the reaction temperature. Furthermore, it was found that the capacitive properties of SnO2/Ni composite foam were related to the pore size of SnO2 film. The SnO2 film with smaller pore size showed higher capacitive properties, in which the porous SnO2/Ni composite foam with pore size of ca.60.0 nm showed high rate capability of 541.0 F g−1 at 10.0 A g−1 and good cycle stability with capacitance retention of 98.1% after 1000 cycles. The high capacitive properties was due to the SnO2 active materials grown on the backbone of Ni foam and porous structure of SnO2 materials, resulting in the reduce of resistance and enhancement of active surface area. Our work not only demonstrates the controlled synthesis of high-quality porous SnO2/Ni composite foam at mild conditions on a large scale, but also provides a universal route for the rational design of supercapacitors with high performance.