Strategic Young Researcher Overseas Visits Programfor Accelerating Brain Circulation 2011“Development of Young ResearchersBased on International Joint Researchon Green Energy Systems”Progress Report1. Name: Koki Urita2. Title: Assistant Professor3. Host Institution: Université Paul Sabatier (France)4. Host Researcher: Proffesor Patrice Simon5. Duration: 1- April- 2014 – 24- March- 20156. Research Topic:Synthesis of pore size-controlled porous carbons for innovative energystorage devices and the system development7. Overview of the Results of the Collaborative Research: 	  	 Fig. 1 TEM images, N2 adsorption isotherms and the pore size distributions of mesoporouscarbons with the average pore size of (a) 25 nm and (b) 80 nm.
 	 Synthesis of porous carbons as electrodes for energy storage devices; The targetmaterials are micro and mesoporous carbons with controlled pore size used aselectrodes for energy storage devices. It was believed that microporous carbon did nothave a potential as electric double-layer (EDL) capacitors because the pore size is notlarge enough against solvated electrolyte ions forming the EDL. Recent studies in Prof.
Patrice Simon’s group where I visited by this program and his research collaboratorreported a dramatic increase in carbon capacitance even with pore size less than 1 nm.
They and our group indicated that the increase was occurred by a desolvation ofelectrolyte ions in micropores from different ways. Since we considered that mostappropriate pore size for improving EDL capacitances was ~ 0.6 nm from our results, Istudied the synthesis of microporous carbons with the narrow pore size distributionaround 0.6 nm. We have not received enough results to apply them to the electrodes ofEDLC and I continue the study as one of the collaborative research. I also synthesizedmesoporous carbons for another goal that is to improve an EDL capacitance bygrafting functional groups on the carbon surface. The Fig.1 shows mesoporouscarbons with the average pore sizes of 25 nm and 80 nm, which I synthesized by usinga silica-opal template method. They will be grafted by a group of Nantes Universityand Prof. Patrice Simon’s group will measure an EDLC performance. We keep up thestudy where I will synthesize mesoporous carbons with narrow pore size distribution.
Development of a capacitive deionization(CDI) system; We propounded new concept ofa capacitive deionization system for desaltingbrackish and seawater. A traditional CDI systemhas limitation of ion storage capacity. After theFig. 2 Schematic of new concept of CDIsystem.

 	  	 

electrodes in CDI system are saturated by ion adsorption, deionization cannot occurwithout an ion release step. We here used a flowable electrode composed porouscarbon spheres and an electrolyte solution to disembogue a constant concentrationsolution. Fig. 2 shows the schematic of concept and the flow capacitive deionizationcell.

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 innovativeporous carbon electrodes. I synthesize pore size-controlled carbons with meso ormicropores and they study the electrochemical performance of them. Especially, as faras mesporous carbon electrodes concerned, another group joins in the project as thesurface treatment. Another is new theme achieved effectively by using a special in-situtechnique of electron microscopy. One of the PhD students in Prof. Patrice Simon’steam 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 onsuspension electrodes without ion exchange membrances.” Electrochem. Commun., 43,18-21 (2014).