Synthesis of hierarchical nanocrystal-based mesoporous materials for electrochemical supercapacitors

The ability to construct well-defined and controlled hierarchical nanostructured porous architectures is desirable for enhancing the performance of electrochem. pseudocapacitors. Here, we propose design rules for improving capacitive energy storage: use of redox-active materials, high surface area for high capacity, mesoporosity for solvent diffusion, and good electronic cond. Previous work on TiO2 nanocrystal-based porous films satisfied many of these requirements. In this work, we build on those initial results using polymer templating of preformed nanocrystals to fabricate high surface area redox-active materials, including Mn3O4 and MnFe2O4. In addn. we have prepd. mesoporous nanocrystal-based films of tin-doped indium oxide (ITO) coated with V2O5. The ITO scaffold provides a conductive pathway and facilitates electron-transfer reactions throughout the V2O5 layer. In these systems, the mesoscale porosity allows facile electrolyte diffusion throughout the material, while the nanocrystals embedded in the pore walls provide a high surface area with ample redox-active sites.