Mixing entropy batteries (MEBs) were reported as a new approach to generate electricity from the difference in salt concentration of two solutions. In general, the MEBs generate electricity from the difference in salt concentration between sea water and freshwater. In such a case, the MEBs become large and the installation place of the MEBs is limited. Therefore, we focused on ionic liquids and zwitterions (ZI) showing a lower critical solution temperature (LCST)-type phase transition. The MEBs using the salinity change due to phase transition eliminate the limitation of size and installation place. Further, these batteries can generate electricity using temperature changes between day and night. In this study, one of our goals is to construct the MEBs that generate electricity from phase transitions caused by small temperature changes. The solution showing LCST-type phase transition can be made by controlling the hydrophobicity of the system. We performed electrolyte solutions showing LCST-type phase transition by adding sodium chloride and water to a N,N,N-tripentyl-3-sulfonyl-1-propaneammonium (N555C3S) as a ZI. The cell was constructed by inserting a Na2Mn5O10 electrode and an AgCl electrode into the upper layer of the electrolyte solution. Using this cell, it was shown that energy can be acquired by small temperature changes. Also, we evaluated how the amount of water and the ZI affect the acquired power in the system.

Construction of the mixing entropy batteries driving the salinity difference by the phase state control of zwitterion/salt solution systems

2019 Fall National Meeting

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