1. High‐Voltage Catholyte for High‐Energy‐Density Nonaqueous Redox Flow Battery.
- Author
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McGrath, Jack, Gautam, Rajeev K., Wang, Xiao, and Jiang, Jianbing Jimmy
- Subjects
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GRID energy storage , *CLEAN energy , *ENERGY density , *POWER density , *FLOW batteries - Abstract
Redox flow batteries (RFBs) with high energy densities are essential for efficient and sustainable long‐term energy storage on a grid scale. To advance the development of nonaqueous RFBs with high energy densities, a new organic RFB system employing a molecularly engineered tetrathiafulvalene derivative ((PEG3/PerF)‐TTF) as a high energy density catholyte was developed. A synergistic approach to the molecular design of tetrathiafulvalene (TTF) was applied, with the incorporation of polyethylene glycol (PEG) chains, which enhance its solubility in organic carbonate electrolytes, and a perfluoro (PerF) group to increase its redox potential. When paired with a lithium metal anode, the two‐electron‐active (PEG3/PerF)‐TTF catholyte produced a cell voltage of 3.56 V for the first redox process and 3.92 V for the second redox process. In cyclic voltammetry and flow cell tests, the redox chemistry exhibited excellent cycling stability. The Li|(PEG3/PerF)‐TTF batteries, with concentrations of 0.1 M and 0.5 M, demonstrated capacity retention rates of ~94 % (99.87 % per cycle, 97.52 % per day) and 90 % (99.93 % per cycle, 99.16 % per day), and the average Coulombic efficiencies of 99.38 % and 98.35 %, respectively. The flow cell achieved a high power density of 129 mW/cm2. Furthermore, owing to the high redox potential and solubility of (PEG3/PerF)‐TTF, the flow cell attained a high operational energy density of 72 Wh/L (100 Wh/L theoretical). A 0.75 M flow cell exhibited an even higher operational energy density of 96 Wh/L (150 Wh/L theoretical). [ABSTRACT FROM AUTHOR]
- Published
- 2024
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