On 28 August 2015 at 12:00 Indrek Tallo will defend his PhD thesis “Synthesis and characterization of new micro-mesoporous carbide derived carbon materials for high energy and power density electrical double layer capacitors” in chemistry in the Faculty of Science and Technology in the University of Tartu.
Supervisors: Professor Enn Lust (PhD), UT Institute of Chemistry
Senior Research Fellow Alar Jänes (PhD), UT Insititute of Chemistry
Research Fellow Thomas Thomberg (PhD), UT Institute of Chemistry
Opponent: Professor Pawel J. Kulesza (PhD), University of Warsaw (Poland)
The geopolitical crises in recent years are often triggered by fights over limited energy resources. This is one of many reasons why it is becoming more and more important to invest in energy security and modern technologies. The latter are largely based on harvesting the energy of the sun and wind, which have to be backed up by various energy storing devices. The production of the necessary energy converter systems as well as high energy and power density storage systems is very difficult without competitive and efficient supercapacitors. In the last decade the commercial supercapacitors have made a great leap in development and their use is growing rapidly. However, their price-performance ratio is still not good enough to implement them on a large scale in electricity networks to make renewable energy more stable. If in great need, the world could meet its energy need from renewable resources even now. However, the price for this is still too high for economically thinking mankind.
To improve the price-performance ratio of supercapacitors there are two options: either lower the cost of production or significantly improve the electrochemical properties of supercapacitors. One of the key components in a supercapacitor is the porous electrode with a very high specific surface area. The morphology and physical characteristics of the electrode determine the supercapacitors electrochemical properties such as power density, capacity and lifetime. For these reasons, it is very important to develop new and better electrode materials for supercapacitors. In the Institute of Chemistry in University of Tartu a lot of work has been done in recent years to study unique carbon materials and their applicability to be used as supercapacitor electrodes. By fairly simple synthesis methods, we are capable of producing carbon materials with exceptional physical and electrochemical properties.
In this work new carbon materials were produced from various carbides by means of high-temperature halogenation. Initially, these materials were physically characterized to better understand their morphology, crystallinity and complex porous structure. Thereafter the carbons were roll-pressed into supercapacitor electrodes and electrochemically analyzed. Clear correlations were established between the electrochemical and physical characteristics of the carbon materials synthesized. As a result, it was determined which materials were better suited for supercapacitor electrodes and which of the physical parameters should be especially kept in mind, when designing new materials for supercapacitors electrodes with a good price-performance ratio.