TY - JOUR
T1 - A Highly Stable, Capacity Dense Carboxylate Viologen Anolyte towards Long-Duration Energy Storage
AU - Wu, Wenda
AU - Wang, Abigail P.
AU - Luo, Jian
AU - Liu, T. Leo
N1 - Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2023/2/6
Y1 - 2023/2/6
N2 - Aqueous organic redox flow batteries (AORFBs) have received increasing attention as an emergent battery technology for grid-scale renewable energy storage. However, physicochemical properties of redox-active organic electrolytes remain fine refinement to maximize their performance in RFBs. Herein, we report a carboxylate functionalized viologen derivative, N,N′-dibutyrate-4,4′-bipyridinium, (CBu)2V, as a highly stable, high capacity anolyte material under near pH neutral conditions. (CBu)2V can achieve solubility of 2.1 M and display a reversible, kinetically fast reduction at −0.43 V vs NHE at pH 9. DFT studies revealed that the high solubility of (CBu)2V is attributed to its high molecular polarity while its negative reduction potential is benefitted from electron-donating carboxylate groups. A 0.89 V (CBu)2V/(NH)4Fe(CN)6 AORFB demonstrated exceptional energy storage performance, specifically, 100 % capacity retention with a discharge energy density of 9.5 Wh L−1 for 1000 cycles, power densities of up to 85 mW cm−2, and an energy efficiency of 70 % at 60 mA cm−2. (CBu)2V not only represents the most capacity dense viologen with pendant ionic groups and also exhibits the longest (1200 hours or 50 days) and the most stable flow battery performance to date.
AB - Aqueous organic redox flow batteries (AORFBs) have received increasing attention as an emergent battery technology for grid-scale renewable energy storage. However, physicochemical properties of redox-active organic electrolytes remain fine refinement to maximize their performance in RFBs. Herein, we report a carboxylate functionalized viologen derivative, N,N′-dibutyrate-4,4′-bipyridinium, (CBu)2V, as a highly stable, high capacity anolyte material under near pH neutral conditions. (CBu)2V can achieve solubility of 2.1 M and display a reversible, kinetically fast reduction at −0.43 V vs NHE at pH 9. DFT studies revealed that the high solubility of (CBu)2V is attributed to its high molecular polarity while its negative reduction potential is benefitted from electron-donating carboxylate groups. A 0.89 V (CBu)2V/(NH)4Fe(CN)6 AORFB demonstrated exceptional energy storage performance, specifically, 100 % capacity retention with a discharge energy density of 9.5 Wh L−1 for 1000 cycles, power densities of up to 85 mW cm−2, and an energy efficiency of 70 % at 60 mA cm−2. (CBu)2V not only represents the most capacity dense viologen with pendant ionic groups and also exhibits the longest (1200 hours or 50 days) and the most stable flow battery performance to date.
KW - Energy Storage
KW - Redox-Flow Battery
KW - Viologen Anolyte
UR - http://www.scopus.com/inward/record.url?scp=85146064471&partnerID=8YFLogxK
U2 - 10.1002/anie.202216662
DO - 10.1002/anie.202216662
M3 - Article
C2 - 36526569
AN - SCOPUS:85146064471
SN - 1433-7851
VL - 62
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 7
M1 - e202216662
ER -