Abstract


Need to develop large scale energy storage device have emerged since few decades to make up for renewable energy source’s weak points. Cyclic Ultra Capacitor (CUCAP), which utilize a flow battery design and are based on the energy storage mechanism of electrochemical capacitors, highly promising for large-scale electrical energy storage since they possess several critical benefits derived from electrochemical capacitors and flow batteries, such as their high power density, long life span, scalable energy capacity, low cost and safe and reliable performance. However, CUcap has many problems to consider as a reliable energy storage device. By designing optimized cell and making high capacity slurries can resolve these problems which represented by over-potential and cycle properties.
In this works, we study that electrochemical performances of CUcap improve by optimizing electrode cell area, porous carbon, ratio between electrolyte, and operation condition. To select suitable porous carbon for CUcap, we have to measure BET value, morphological properties and specific capacitance of two kind porous carbons. After the process, A carbon slurry with various ratio of a selected porous carbon electrode combined with a conducting agent (AC0830 : Sup-P = 7:3) to the electrolyte (1M TEABF4 in acetonitrile) was made for using the flowable electrode. The tests about optimizing electrode channel depth and electrolyte ratio were conducted under non-flow condition. Also, we investigate effect of changing active material’s ratio in slurry electrode under the different operation conditions. The operation conditions are non-flow mode, flow mode and stack flow mode. In this test, slurry electrodes were prepared that have different active material ratio in fixed electrolyte amount. The best ratios of active materials at each operation condition were different. Having more adsorption-site is more important than electric conductivity to cell performance under the low resistance condition like non-flow mode. But having higher electrical conductivity on slurry electrode is more benefit electrochemical performance under stack-flow mode which has harsh resistance.