Electrochemical cell recharging by solvent separation and transfer processes

Yohei Matsui,Takahiro Suzuki,Shohji Tsushima,Makoto Kawase

doi:10.1038/s41598-022-07573-x

Yohei Matsui, Takahiro Suzuki + Show 2 more

Open Access

https://doi.org/10.1038/s41598-022-07573-x

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Abstract

Electrochemical conversion and storage of unutilized renewable energy will contribute to decarbonization. Here, we create the concept of a liquid electrochemical cell that discharges between the anodic and cathodic sides by reverse reactions of the same redox couple in different solvation states, which are created by differences in the mixture ratios of two solvents called the main solvent (MS) and the transferred solvent (TS). The cell can be charged by a transfer of the TS between the discharged anolyte and catholyte. As an example, we demonstrate a cell utilizing a ferro-/ferricyanide redox couple. Stable discharging and charging via the proposed method is achieved by utilizing water (MS) and acetone (TS). Additionally, dominating factors in the design of a high-performance system are discussed, focusing on the electron acceptability of the MS and the TS. The cell voltages are successfully tuned, and a cell voltage of 0.63 V is achieved by the combination of dimethyl sulfoxide (MS) and water (TS). Moreover, the cell can be customized by various electrochemical reaction systems, which can allow multiple options for the charging processes. This concept provides new approaches for the utilization of diverse energy sources as an input for the charging of electrochemical cells.

Highlights

As wind energy, wave energy, tidal energy and small-scale h ydroenergy[20–23]
We experimentally show open-circuit voltages (OCVs) for
The addition of acetone leads to a difference in the solvent components on the right side (L-transferred solvent (TS) side) and left side (H-TS side), implying that the addition of acetone (TS) results in a change in the solvation states of the redox couple on the higher TS ratio (H-TS) side and contributes to a change in the redox potential

Summary

Introduction

As wind energy, wave energy, tidal energy and small-scale h ydroenergy[20–23]. To broaden the field of applications of electrochemical devices in energy systems, electrochemical cells with totally new concepts should be pursued. Anodic and cathodic reactions are reverse redox reactions of the same redox couple (R and O) This system appears to be similar to general concentration c ells[24–27], the installation of the TS leads to differences in the solvation states of R and O between H-TS and L-TS and contributes to a larger cell voltage. Note that the directions of the reactions are dependent on the components applied as a redox couple, MS, TS or other solutes Another remarkable characteristic of a SDC is its unique charging process called solvation recovery. Discharging a SDC can be generally considered as a conversion of the difference in the solvation free energy between the anodic and cathodic solvents for redox couples into electrical energy, and solvation recovery. Dominating factors to design an SDC with a large cell voltage are discussed based on a solution chemistry-based strategy

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