Strategic Young Researcher Overseas Visits Programfor Accelerating Brain Circulation 2011
“Development of Young Researchers
Based on International Joint Research
on Green Energy Systems”
Progress Report

1. Name: Koki Urita
2. Title: Assistant Professor
3. Host Institution: Université Paul Sabatier (France)
4. Host Researcher: Proffesor Patrice Simon
5. Duration: 1- April- 2014 – 24- March- 2015
6. Research Topic:
Synthesis of pore size-controlled porous carbons for innovative energy
storage devices and the system development
7. Overview of the Results of the Collaborative Research:Fig. 1 TEM images, N2 adsorption isotherms and the pore size distributions of mesoporous
carbons with the average pore size of (a) 25 nm and (b) 80 nm.

Synthesis of porous carbons as electrodes for energy storage devices; The target
materials are micro and mesoporous carbons with controlled pore size used as electrodes forenergy storage devices. It was believed that microporous carbon did not have a potential aselectric double-layer (EDL) capacitors because the pore size is not large enough against
solvated electrolyte ions forming the EDL. Recent studies in Prof. Patrice Simon’s groupwhere I visited by this program and his research collaborator reported a dramatic increase incarbon capacitance even with pore size less than 1 nm. They and our group indicated that theincrease was occurred by a desolvation of electrolyte ions in micropores from different ways.
Since we considered that most appropriate pore size for improving EDL capacitances was ~0.6 nm from our results, I studied the synthesis of microporous carbons with the narrow poresize distribution around 0.6 nm. We have not received enough results to apply them to theelectrodes of EDLC and I continue the study as one of the collaborative research. I alsosynthesized mesoporous carbons for another goal that is to improve an EDL capacitance bygrafting functional groups on the carbon surface. The Fig.1 shows mesoporous carbons withthe average pore sizes of 25 nm and 80 nm, which I synthesized by using a silica-opal
template method. They will be grafted by a group of Nantes University and Prof. Patrice
Simon’s group will measure an EDLC performance. We keep up the study where I will
synthesize mesoporous carbons with narrow pore size distribution.

Development of a capacitive deionization (CDI)system; We propounded new concept of a capacitive
deionization system for desalting brackish andseawater. A traditional CDI system has limitation ofion storage capacity. After the electrodes in CDI
systemaresaturatedbyion

adsorption,

Fig. 2 Schematic of new concept of CDI
system.

deionization cannot occur without an ion release step. We here used a flowable electrodecomposed porous carbon spheres and an electrolyte solution to disembogue a constantconcentration solution. Fig. 2 shows the schematic of concept and the flow capacitive
deionization cell.

8. Deployment Plans for Future Collaborative Research:
I will continue collaboration on the two research topics with Prof. Patrice Simon. One that is
an ongoing project in this research program is the development of innovative porous carbon
electrodes. I synthesize pore size-controlled carbons with meso or micropores and they study
the electrochemical performance of them. Especially, as far as mesporous carbon electrodesconcerned, another group joins in the project as the surface treatment. Another is new theme
achieved effectively by using a special in-situ technique of electron microscopy. One of the PhD
students in Prof. Patrice Simon’s team will come to Nagasaki University to carry out
collaborative research this year.

9. The List of Collaborative Research Progress:Publication(s)1) K. B. Hatzell, E. Iwama, A. Ferris, B. Daffos, K. Urita, T. Tzedakis, F. Chauvet, P. –L.
Taberna, Y. Gogotsi and P. Simon “Capacitive deionization concept based on suspension
electrodes without ion exchange membrances.” Electrochem. Commun., 43, 18-21 (2014).