Temperature Dependent Study of AcFc-FeIII(acac)3 Redox Couple for Non-Aqueous Redox Flow Battery

Abstract

Energy storage is a vital aspect for the successful implementation of renewable energy resources on a global scale. Non-aqueous redox flow battery (NARFB) is one of the primary response to fulfill the next generation energy demand.1–6 This study describes the temperature dependence electrochemical analysis of acetyl ferrocene (AcFc) and iron(III) acetyl acetonate ([Fe(acac)3]) for NARFBs. An electrochemical cell consisting of AcFc and ([Fe(acac)3]) as catholyte and anolyte species, respectively, was constructed with a cell voltage of 1.41 V and Coulombic efficiencies >99% for up to 50 total cycles at 25o C (RT) and 0o C. Rotating ring disk electrode (RRDE) experiments suggest that diffusion coefficient decreases as the temperature decreases but overall storing capacity far better than aqueous redox flow battery (ARFBs). The electrochemical kinetic rate constant (k0) of AcFc found larger than Fe(acac)3 but remains similar at both temperatures. NMR study shows no structural change in changing temperature and after battery experiments. References (1) Mazumder, M. M. R.; Burton, A.; Richburg, C. S.; Saha, S.; Cronin, B.; Duin, E.; Farnum, B. H. Controlling One-Electron Vs Two-Electron Pathways in the Multi-Electron Redox Cycle of Nickel Diethyldithiocarbamate. ECS Meet. Abstr. 2021, MA2021-01 (1), 52–52. https://doi.org/10.1149/ma2021-01152mtgabs.(2) Islam, R.; Mazumder, M. M. R.; Farnum, B. H. Solvent Dependent Spectroscopic and Electrochemical Studies of Nickel (II) Diethyldithiocarbamate for Energy Storage. ECS Meet. Abstr. 2021, MA2021-01 (1), 54–54. https://doi.org/10.1149/ma2021-01154mtgabs.(3) Saha, S.; Sahil, S. T.; Mazumder, Md. M. R.; Stephens, A. M.; Cronin, B.; Duin, E. C.; Jurss, J. W.; Farnum, B. H. Synthesis, Characterization, and Electrocatalytic Activity of Bis(Pyridylimino)Isoindoline Cu( ii ) and Ni( ii ) Complexes. Dalton Trans. 2021, 10.1039.D0DT03030A. https://doi.org/10.1039/D0DT03030A.(4) Mazumder, M. M. R.; Farnum, B. H. Two One Electron vs One Two-Electron Redox System of Nickel Diethyldithiocarbamate for Redox Flow Battery; ACS, 2021. https://doi.org/10.1021/scimeetings.1c00951.(5) Mazumder, M. M. R.; Farnum, B. H; Burton Andricus. Mechanistic Study of Multi-Electron Redox Cycle of Nickel Dithiocarbamate Complex for Redox Flow Battery Application; ACS, 2021. https://doi.org/10.1021/scimeetings.1c00387.(6) Mazumder, M. M. R. Ni(IV/II) Redox Couple 2e- Reversibility Improvement for Redox Flow Battery. ECS Meet. Abstr. 2021, MA2021-02 (5), 1855–1855. https://doi.org/10.1149/ma2021-0251855mtgabs. Figure 1