ORALS
SESSION: ElectrochemistryTueAM-R2
| Amatore International Symposium on Electrochemistry for Sustainable Development |
| Tue Nov, 6 2018 / Room: Copacabana B (150/1st) | |
| Session Chairs: Tsuyoshi Hoshino; Session Monitor: TBA |
12:10: [ElectrochemistryTueAM03]
Vitamin Based Redox Active Organic Molecules for Energy Storage Sherman
Lauw
1 ; Raymond
Shi
1 ; Bao Yun
Foo
1 ;
Richard
Webster1 ;
1Nanyang Technological University, Singapore, Singapore;
Paper Id: 220
[Abstract] Conventional batteries function by storing the electrical energy inside solid electrodes, while redox flow batteries (RFBs) are able to store their electrical energy within molecules in solution. RFBs have a number of proposed advantages over conventional batteries; including, (i) the huge number of molecular systems that can potentially be utilized, (ii) the ability to tune the voltage over a wide range, (iii) simple electrode designs that do not change morphologies during charging and discharging, and, (iv) cost-effectiveness for large-scale energy storage. Nevertheless, RFBs suffer several drawbacks in their implementation compared to conventional solid-state batteries, such as their relatively low energy densities due to low molecular solubility, and the increased reactivity of the redox active species. In this study, two fully organic molecular systems were identified that were able to function as the anolyte and catholyte in solution phase batteries. The systems studied were based on modified forms of the naturally occurring vitamin E [1,2] and vitamin K<sub>1</sub> [3]. The systems were chosen because of their suitable reduction (vitamin K<sub>1</sub>) and oxidation (vitamin E) potentials measured by cyclic voltammetry, because the compounds had long-lifetimes in their reduced/oxidized states, and because the compounds were highly soluble in acetonitrile containing acid/water. Furthermore, the molecules were found to be able to be utilized in a "mixed-reactant" system were the solutions had exactly the same composition in both compartments (anolyte and catholyte). The lifetime of the reduced forms of vitamin K<sub>1</sub> were affected by the acidity of the solution, which allowed the pH of the solution to be adjusted to allow for the optimal stabilities of the reduced/oxidized quinonoids. Repeated electrolysis experiments in acidified solutions indicated that the systems were fully chemically reversible and so suitable for long-term energy storage applications.
References:
[1] L. L. Williams, R. D. Webster. J. Am. Chem. Soc. 126 (2004) 12441-12450.\n[2] H. M. Peng, B. F. Choules, W. W. Yao, Z. Zhang, R. D. Webster, P. M. W. Gill, J. Phys. Chem. B 112 (2008) 10367-10374.\n[3] Y. Hui, E. L. K. Chng, C. Y. L. Chng, H. L. Poh, R. D. Webster, J. Am. Chem. Soc. 131 (2009) 1523-1534.
