Manganese-Based Redox Flow Batteries for Grid Energy Storage

Redox flow batteries (RFBs) are secondary battery systems suitable for large-scale, stationary energy storage applications, and are capable of storing large quantities of energy (MWh) and power (MW).¹ One principle advantage of flow batteries is the ability to decouple energy and power density, and scale both independently. The all-vanadium RFB represents the current state-of-the-art in flow battery technology, but uses expensive ion exchange membranes including Nafion®, and the relatively high cost of vanadium leads to expensive electrolytes.²

The development of manganese-based anolytes as a suitable alternative to vanadium anolytes for redox flow batteries is attractive for various reasons, including a higher reversible potential for Mn²⁺/Mn³⁺ than VO²⁺/VO₂⁺, higher natural abundance, and lower cost than vanadium. Flow battery anolytes based on the Mn²⁺/Mn³⁺ redox couple have been reported in the literature, and the high standard electrode potential of Mn²⁺/Mn³⁺ (1.51 V) has been utilized in manganese anolyte (Mn²⁺/Mn³⁺)/vanadium catholyte (V²⁺/V³⁺) redox flow batteries, featuring a theoretical open circuit voltage of 1.77 V.^2,3 The usage of manganese anolytes can lead to a higher cell voltage, yet the disproportionation reaction of Mn³⁺ is a technical hurdle that needs to be resolved in order for manganese-based anolytes to find widespread utility in redox flow batteries.^2,4

This presentation will disclose investigations on the development of manganese-anolyte based redox flow batteries, and will show results from two different systems, including Ti/Mn, and V/Mn. Half–cell and full cell performance metrics, including cycle life testing, will be presented for each system.

References

1) Wang, W. et al. J. Power Sources. 2012, 216, 99.

2) Xue, F.-Q. et al. Electrochimica Acta. 2008, 53, 6636.

3) Hong, T.; Xue, F. “Investigation on manganese (Mn²⁺/Mn³⁺)-vanadium (V²⁺/V³⁺) redox flow battery.” 2009 Asia-Pacific Power and Energy Engineering Conference (APPEEC).

4) Swartz, C. R.; Lipka, S. M.; Rogers, F. III; Chen, R.; Kodenkandath, T. “Aqueous Manganese-Based Electrolytes for Redox Flow Batteries.” ECS abstract MA2014-02, 616.