Mosaic-Structured SnO2@C Porous Microspheres for High-Performance Supercapacitor Electrode Materials

Abstract

Mosaic-structured SnO2@C microspheres with hierarchical porosity were designed and synthesized via an ethanol-thermal carbonization and steam activation method. SnO2 nanoparticles were embedded uniformly within the porous carbon microspheres. These SnO2@C porous microspheres have been characterized by XRD, FESEM, TEM, XPS and tested as electrode materials for high-performance supercapacitors. The SnO2 nanoparticles were embedded within the hierarchically porous carbon microspheres, and thus the conductivity and stability was improved. Furthermore, the channel of porous carbon microspheres make the electrolyte fully contacts with SnO2 nanoparticles, hence the as-prepared SnO2@C porous microspheres possess the characteristic of pseudocapacitors and ECDLs. In addition, uniformly spherical SnO2@C particles possess the enhanced volumetric density of the electrode materials make the further charge storage in supercapacitor. Experimental results show that the SnO2@C microspheres exhibit a super specific capacitance up to 420 F g−1 in galvanostatic charge/discharge measurements and high energy density of 34.2 Wh kg−1, it also possess a good conductivity as well as electro-cycling stability.