High-Voltage Catholyte for High-Energy-Density Nonaqueous Redox Flow Battery.
Angew Chem Int Ed Engl
; : e202407906, 2024 Jun 06.
Article
in En
| MEDLINE
| ID: mdl-38842475
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 3.56â
V for the first redox process and 3.92â
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 0.1â
M and 0.5â
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 129â
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 72â
Wh/L (100â
Wh/L theoretical). A 0.75â
M flow cell exhibited an even higher operational energy density of 96â
Wh/L (150â
Wh/L theoretical).
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2024
Document type:
Article
Affiliation country:
United States