SnO2 mesoporous nanostructures serve as battery-type cathode for hybrid supercapacitor with superior electrochemical performance

Abstract

Herein, the mesoporous tin dioxide (SnO₂) electrode materials with large specific surface areas were simply prepared through an initial solvothermal method in a mixed solvent of glycerol, isopropanol, and de-ionized water, along with a post annealing treatment in air. The average size of SnO₂ varied from 1 μm to 0.5 μm by changing the volume ratio of glycerol to isopropanol, and the product was denoted as SnO₂-5/35 and SnO₂-20/20, respectively. The electrochemical tests revealed that such SnO₂ electrode materials exhibited battery-type response. The SnO₂-5/35 delivered the greatest specific capacity of 219.3 C g⁻¹, higher than 200.4 C g⁻¹ for SnO₂-20/20 electrode. In the configuration of hybrid supercapacitor (HSC) device, the SnO₂ served as the cathode and activated carbon (AC) was utilized as the anode. The SnO₂-5/35//AC HSC exhibited an energy density of 33.6 W h kg⁻¹ at the power density of 946.9 W kg⁻¹. In contrast, the SnO₂-20/20//AC HSC delivered an inferior specific energy of 28.5 W h kg⁻¹. Both HSCs showed excellent cyclic performance over 6000 cycles under a high current load of 10 A g⁻¹. These results indicate that the SnO₂ materials, especially SnO₂-5/35, holds significant application potential in the field of electrochemical energy storage. Additionally, the current synthesis method can be extended to the preparation of other metal oxides with extraordinary electrochemical property for the practical applications in supercapacitors.