(774d) Electrolyte Optimization for Fe/V Redox Flow Battery System

Electrolyte
optimization for Fe/V redox flow battery system

Bin Li, Wei Wang, Zimin
Nie, Vince Sprenkle, Baowei Chen, Xiaoliang Wei, Qingtao Luo, Guanguang Xia,
Liyu Li and Zhenguo Yang

Pacific Northwest National Laboratory

902 Battelle Boulevard, PO Box 999, Richland, WA
99354

Abstract

Redox flow batteries
(RFBs) research and development have recently enjoyed a renaissance primarily
due to their ability to store large amounts of power and energy, up to multi-MW
and multi-MWh, respectively, for renewable energy integration or smart-grid
deployment.¹ Broad
market penetration, however, has not been achieved due to several limitations
such as high cost, instability in long-term operation, and narrow operational
temperature range, etc. Recently invented Fe/V redox flow battery (IVRFB) has
attracted more and more attentions due to its long-term cycling stability and
the freedom to utilize membranes other than expensive Nafion.² In this
study, extensive matrix study was performed on the Fe/V electrolyte in order to
determine the relationships of the composition, state of charge (SOC), and
temperature stability. As we know, the temperature stability of the RFB systems
is of paramount importance for practical use. A RFB system with wider temperature
stability will not only enable the RFB to be deployed with less geographical
limitation, but also possibly eliminate the active temperature management
system reducing parasitic loss. As previously reported, the current Fe/V
electrolyte cannot be operated or stored at lower temperatures (≤ 0^oC)
due to the precipitations (FeCl₂).  In this research, factors
influencing the stability of electrolytes in both positive and negative
half-cells with different SOCs at different temperatures from -10^oC
to 40^oC were systematically studied. Through the optimization of the
electrolyte composition, an electrolyte stable in the temperature range from -5^oC
to 40^oC was identified. Electrolyte stability data and IVRFB flow
cell cycling performances using low-cost separators will be presented (Fig.1).

Fig.1
Cycling performances of optimized Fe/V electrolytes

References

(1)        Yang,
Z.; Zhang, J.; Kintner-Meyer, M. C. W.; Lu, X.; Choi, D.; Lemmon, J. P.; Liu,
J. Chemical Reviews 2011, 111, 3577.

(2)        Wang,
W.; Kim, S.; Chen, B.; Nie, Z.; Zhang, J.; Xia, G.-G.; Li, L.; Yang, Z. Energy
& Environmental Science 2011, 4, 4068.