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Supercapacitor have been widely researched in order to apply many fields such as a hybrid electric vehicles, high pulse power sources, and emergency power sources requiring high power instantly. However, supercapacitor has low energy density compared to batteries. In order to increase the energy density of supercapacitor, electrode is the very important. Until now, porous carbons, which have low energy density (5~10 Wh kg-1) are the widely used for electrode materials. Recently, many reports have been released using a surface treated carbon or graphene, RGO and CDC, etc. However, these ways have much time and costs in order to compensate the energy. In this study, the CO2 laser treated carbon electrode is investigated for high-performance supercapacitors. First of all, in order to investigate the effect of CO2 laser radiation on energy density and microstructure, carbon electrode was fabricated as a mixture of active material, conductive material, and PVDF binder. The mixed slurry with NMP was coated onto an aluminum plate and dried at 100 oC for 12h. And then CO2 laser was radiated onto the surface of the carbon electrode. A 2032coin cell was assembled with the TEABF4 as electrolyte and separator. The microstructure difference was investigated with SEM and cyclic voltammetry tests also were carried out in the potential range of 0 to 2.7 V for comparison to CO2 laser radiated and un-radiated carbon electrode.

Thermal batteries have been used for many military applications such as missiles and ordnance devices. As the thermal battery is composed of anode, cathode, MgO based-molten salt electrolyte and additional heat source, its specific energy density is lower than those of commercial batteries. By means of substituting MgO based-electrolyte to increase energy density of thermal batteries, we have indentified various ionic solid electrolytes such as LLT(La0.5Li0.5TiO3), LSTZ(Li3/8Sr7/16Ta3/4Zr1/4O3) and LLZ(Li7La3Zr2O12). As a ruslt, we found out that the LLZ with additivies, Ca and Nb, presents not only excellent ionic conductivity but also stable discharge characteristics at high temperature(≈ 300oC). Additionally, we have verified that the LLZ solid electrolyte is suitable for the full scale of thermal batteries with high energy density.

A wide variety of supercapacitors has been developed for many high-power energy storage application. Especially, flexible supercapacitors with thin electrodes are being needed for powering flexible electronics for military applications. In this study, the inkjet-printed graphene electrode is investigated for high-performance thin film supercapacitors. In order to make the ink for printing, graphene flakes ware dispersed in a solvent and then printed onto a metal foil. The electrodes were inkjet-printed with the various graphene flake size and the film thickness. After the printing, the electrodes were dried to remove solvent. These electrodes were sealed together with the electrolyte and separator, and then assembled into a coin cell. The microstructures of the printed graphene electrodes were analyzed by SEM, TEM and XRD. The electrochemical performances were also investigated.

A Li-Si/FeS2 electrochemical system, which is widely used for thermal batteries, has limited energy density and power capability due to the partial utilization of the active materials. A single cell with a molten lithium anode or a molten sulfur cathode has a high energy density with a high open circuit voltage compared to that with a Li-Si/FeS2 couple. The main challenges in the molten electrodes arise from the instability of liquid active materials which can directly react with the other electrode and results in catastrophic thermal runaways, such as vent, fire or even explosion. For the practical application to thermal batteries which operates at above the melting point of the active electrode materials, the immobilization of the molten electrode is inevitably required. The combination of the porous metal foams with liquid active materials is found to be quite effective solution to attain unconventionally high energy density as well as high power capability. In this study, highly conductive nickel foam electrodes are incorporated with pure lithium or sulfur. The electrochemical characteristics are investigated along with the single cell tests and the microstructural analysis.