About Waki Lab

Research Themes

With the depletion of non-renewable resources and global warming, renewable clean energy has become paramount towards sustainable living on earth. Among these clean energy conversion and storage systems, our laboratory primarily focuses on fuel cells, photovoltaic cells and lithium batteries.

Perovskite solar cells

Perovskite solar cells (PSCs) have attracted a lot of interest because of their high efficiency and low cost. The application of a hole transportation material (HTM) has proven to be an effective way to boost PSC efficiency. However, the use of HTMs has led to cell degradation. In our lab, we use a self-standing buckypaper (BP) formed by multi-walled carbon nanotubes to replace the traditional HTM / Au electrode and aim for PSCs with high efficiency, high durability, and low cost.

For details:https://www.titech.ac.jp/english/news/2019/045489

Fuel cells

Structurally controlled carbon nanotubes (MWCNTs) are investigated as the cathode and anode for fuel cells application, respectively. To realize the new structure of DMWCNT (defective-MWCNTs) with nano-holes defects, an original method to make crystal defects on the surface of multi-walled carbon nanotubes using nano-oxide particles as the catalysts for breaking the carbon surface in air at low temperature was developed in our lab.

The oxygen reduction reaction (ORR) characteristics which are important for the fuel cell applications are studied to clarify the roles of defects and functional groups.. So far, we have achieved the highest on-set potential of ORR for the non-doped carbons reported, and also the highest Li ion storage capacity among MWCNT electrodes.

Dye-Sensitized Solar Cells (DSSCs)

 In order to achieve further improvements in electron transport and overall efficiency, many studies have focused on DSSC photoanodes containing one-dimensional nanostructures such as nanotubes, nanofibers, and nanorods. Among these materials, ZnO nanorod array electrodes have attracted significant attention due to their favorable properties such as electron mobility and ease of fabrication. In our lab, we modify the ZnO nanorod array by the addition of second metal to change both the morphology and electronic properties of the ZnO electrode.