Electrode design of energy storage concrete devices for improving energy storage and cyclic performance

As the development of energy storage concrete devices (ESCs) is still nascent, their electrochemical properties remain largely unknown. Elucidation of the basic mechanism of ESCs will lead to the establishment of general-purpose design technology. In this paper, based on the electrostatic field theory of capacitors, we investigated the effect of electrodes design on the electrochemical properties of ESCs and clarified part of the energy storage mechanism of ESCs. In addition, it was shown that the energy storage capacity of ESCs can be dramatically improved by appropriate electrode design, and a guideline for electrode selection to improve the energy storage performance of ESCs was also presented. It was found that the energy storage performance of ESCs can be improved by narrowing the distance between the electrodes. This result suggests that polarization of potassium geopolymer matrix near the electrodes plays a influential role in the energy storage mechanism of ESCs. It was also found that the energy storage performance can be improved by using fine mesh electrodes, which increases the effective contact area for energy storage. On the other hand, durability becomes an issue if the mesh opening is too small because smaller mesh opening leads to thinner mesh wires. The tradeoff therefore needs to be considered between energy storage performance and durability. A remarkable performance of ESCs was achieved by selecting an appropriate electrode mesh size for cyclic performance of charging and discharging even after 100,000 cycles.