Fabrication of Hybrid Capacitor Electrodes Using Japanese Distilled Liquor Waste and Waste Paint
Authors: Sano Tomoya , Tashima Daisuke 
Published: December 2024

Until recently, Japan's energy has been fully dependent on non-renewable resources such as coal, petroleum, and natural gas (LNG). Since these are scarce in terms of reserves, Japan has largely imported them from other countries. However, in recent years, the introduction of renewable energy sources that do not rely on fossil fuels has been increasing due to global conditions and the influence of the goal of carbon neutrality. Renewable energies do not rely on fossil fuels, but their generation is affected by weather and other factors, making stable supply uncertain. Therefore, research on storage batteries is being actively conducted to strengthen the supply by using storage batteries and other technologies to store electricity. [1]
One type of storage battery, the electric double layer capacitor (EDLC), has the advantages of high output and long life, but has the disadvantage of low energy density. Rechargeable batteries, which are ordinary storage batteries, have the disadvantage of a small service life due to the chemical reaction involved. Therefore, it is expected that hybrid capacitors will be created by combining the electrodes of the two batteries to overcome their disadvantages. [2]
Furthermore, shochu, a Japanese alcoholic beverage, produces waste called Japanese distilled liquor waste during production, which is difficult to dispose of. Kyushu accounts for 90% of all shochu shipments in Japan and is plagued by large amounts of Japanese distilled liquor waste. [3] For this reason, it is hoped that the application of Japanese distilled liquor waste and waste paint, which is an industrial waste, to electrodes in Kyushu will simultaneously aim to lower the cost of storage batteries and dispose of industrial waste and contribute to achieving the goals of the SDGs.
This research group has previously developed an EDLC using Japanese distilled liquor waste [4]. Furthermore, since waste paint contains titanium dioxide, a metal oxide, the use of this material is expected to lead to the creation of a hybrid capacitor with high energy efficiency and long life. In this paper, the negative electrode was prepared using activated carbon made from Japanese distilled liquor waste by two-step activation, and the positive electrode was prepared using carbide made from waste paint by carbonization. The electrodes were then measured by cyclic voltammetry (CV) to evaluate their basic performance as hybrid capacitor electrodes.
The results showed that the electrode fabricated from waste paint had a low capacity, with the largest electrode having a capacity of 26.99 F/g, although potassium hydroxide (KOH) solution was used as the electrolyte during the performance evaluation. In contrast, when sulfuric acid was used as the electrolyte, the capacity was 46.87 F/g, an improvement of 1.7 times. This suggests that it is better to use sulfuric acid as the electrolyte for electrodes made from waste paint.
In addition, previous studies have completed the performance evaluation of electrodes made from Japanese distilled liquor waste, and activated carbon with an activation temperature of 800-1000°C showed the best performance as an electrode. [5]
In the future, coin cell electrodes will be fabricated from the best capacitance of each of the materials evaluated, and their performance as hybrid capacitors will be evaluated by combining them.
References
[1] Lere. Deguenon, Daniel. Yamegueu,”
Overcoming the Challenges of Integrating Variable Renewable Energy to the Grid: A Comprehensive Review of Electrochemical Battery Storage Systems”
, Journal of Power Sources, Volume 580, 233343, 2023.
[2] Mustafa. Elgin. Shahin, “
A Comprehensive Review on Supercapacitor Applications and Development”
, MDPI, 15(3), 674, 2022.
[3] T. Eguchi, D. Tashima, M. Fukuma, S. Kumagai, “
Activated carbon derived from Japanese distilled liquor waste: Application as the electrode active material of electric double-layer capacitors
”, Journal of Cleaner Production, Vol.259, 120822 June 2020.
[4] D. Tashima, “
Energy Storage Devices from Industrial Waste - Eco-friendly Capacitor Development through Resource Reuse”
, Journal of the Institute of Electrical Engineers of Japan, Vol.139, No.8, pp.542-545, 2019.
[5] Takuya. Eguch, “
Application of Activated Carbon from Japanese distilled liquor waste to Electric Double Layer Capacitors”
, Proceedings of the Kyushu Branch Joint Convention of the Institutes of Electrical and Related Engineers 12-2P-08, 2016

Figure 1