Characteristics of Zinc Secondary Batteries Encapsulated in Cement with Aqueous Solution System

Abstract

　As a measure against global warming, efforts to utilize renewable energy and promote energy conservation are being carried out on a global scale. At the same time, in response to the increasing occurrence of natural disasters such as typhoons and heavy rains in recent years, the development of autonomous and decentralized energy supply systems on a regional scale is progressing. Large-scale energy storage systems capable of maintaining long-term safety are becoming increasingly widespread.

　Among them, large-scale lithium-ion batteries have a high energy density. However, their manufacturing process involves significant CO₂ emissions. Furthermore, their electrolytes contain organic solvents, and their exterior components and insulation parts require a substantial amount of metal and resin. Therefore, when modularized and utilized as an energy storage system, they cannot necessarily be considered a part of a decarbonized and circular society model. If a battery compatible with conventional concrete structures could be directly embedded within them, the aforementioned materials would no longer be necessary, enabling the development of a new environmentally friendly energy storage system. The construction industry accounts for 20% of industrial waste, half of which consists of concrete debris and siding waste. Thus, this approach would also be beneficial for reuse applications.

　In this study, we investigated the feasibility of using cement-encapsulated aqueous zinc secondary batteries. Charging and discharging tests were conducted on Mn/Zn secondary batteries encapsulated in cement and immersed in an 8 mol・dm^－3 potassium hydroxide solution, yielding a discharge capacity of approximately 150 mAh・g^－1. Additionally, the cycle characteristics of cement mixed with siding material showed significant improvement compared to those without additives.