TY - JOUR
T1 - A trifunctional electrolyte for high-performance zinc-iodine flow batteries
AU - Jian, Q. P.
AU - Wu, M. C.
AU - Jiang, H. R.
AU - Lin, Y. K.
AU - Zhao, T. S.
N1 - Funding Information:
The work described in this paper was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. T23-601/17-R) and HKUST fund of Foshan (Grant No. FSUST19-FYTRI06).
Funding Information:
The work described in this paper was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region , China (Project No. T23-601/17-R ) and HKUST fund of Foshan (Grant No. FSUST19-FYTRI06 ).
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/1
Y1 - 2021/2/1
N2 - Zinc-iodine flow battery (ZIFB) holds great potential for grid-scale energy storage because of its high energy density, good safety and inexpensiveness. However, the performance of ZIFB is hindered by conventional electrolyte that offers low ionic conductivity, suffers from iodine precipitation and triggers severe Zn dendrite growth. Here, we report an NH4Br improved electrolyte to address the issues simultaneously. The addition of NH4Br enhances the ionic conductivity of electrolyte from 120 to 180 mS cm−1. Meanwhile, Br− ions complex with I2 forming soluble I2Br−, which frees up I− ions and thus unlocks the battery capacity, while NH4+ ions complex with Zn2+ ions to mitigate Zn dendrite formation with the electrostatic shielding effect. Experimental results reveal that the improved electrolyte promotes the kinetics and reversibility of both positive and negative redox couples. A ZIFB with the improved electrolyte delivers a high energy efficiency (85%), a high charge capacity (35 A h L−1) and a long cycle life (100 cycles without degradation) at 40 mA cm−2, while conventional ZIFB shows an energy efficiency of 80%, a charge capacity of 25 A h L−1, and a short cycle life of only around 15 cycles. These encouraging results indicate that NH4Br, a cost-effective salt, offers great prospects for high-performance ZIFB applications.
AB - Zinc-iodine flow battery (ZIFB) holds great potential for grid-scale energy storage because of its high energy density, good safety and inexpensiveness. However, the performance of ZIFB is hindered by conventional electrolyte that offers low ionic conductivity, suffers from iodine precipitation and triggers severe Zn dendrite growth. Here, we report an NH4Br improved electrolyte to address the issues simultaneously. The addition of NH4Br enhances the ionic conductivity of electrolyte from 120 to 180 mS cm−1. Meanwhile, Br− ions complex with I2 forming soluble I2Br−, which frees up I− ions and thus unlocks the battery capacity, while NH4+ ions complex with Zn2+ ions to mitigate Zn dendrite formation with the electrostatic shielding effect. Experimental results reveal that the improved electrolyte promotes the kinetics and reversibility of both positive and negative redox couples. A ZIFB with the improved electrolyte delivers a high energy efficiency (85%), a high charge capacity (35 A h L−1) and a long cycle life (100 cycles without degradation) at 40 mA cm−2, while conventional ZIFB shows an energy efficiency of 80%, a charge capacity of 25 A h L−1, and a short cycle life of only around 15 cycles. These encouraging results indicate that NH4Br, a cost-effective salt, offers great prospects for high-performance ZIFB applications.
KW - Energy storage
KW - High energy density
KW - Supporting electrolyte
KW - Zinc dendrite
KW - Zinc-iodine flow batteries
UR - http://www.scopus.com/inward/record.url?scp=85097071762&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2020.229238
DO - 10.1016/j.jpowsour.2020.229238
M3 - Journal article
AN - SCOPUS:85097071762
SN - 0378-7753
VL - 484
JO - Journal of Power Sources
JF - Journal of Power Sources
M1 - 229238
ER -
