Hydrogen/manganese hybrid redox flow battery

Abstract

Electrochemical energy storage is a key enabling technology for further integration of renewables sources. Redox flow batteries (RFBs) are promising candidates for such applications as a result of their durability, efficiency and fast response. However, deployment of existing RFBs is hindered by the relatively high cost of the (typically vanadium-based) electrolyte. Manganese is an earth-abundant and inexpensive element that is widely used in disposable alkaline batteries. However it has hitherto been little explored for RFBs due to the instability of Mn(III) leading to precipitation of MnO 2 via a disproportionation reaction. Here we show that by combining the facile hydrogen negative electrode reaction with electrolytes that suppress Mn(III) disproportionation, it is possible to construct a hydrogen/manganese hybrid RFB with high round trip energy efficiency (82%), and high power and energy density (1410 mW cm −2 , 33 Wh l −1 ), at an estimated 70% cost reduction compared to vanadium redox flow batteries.

Hydrogen/functionalized benzoquinone for a high-performance regenerative fuel cell as a potential large-scale energy storage platform

“…An even more economical RFC is the recently reported hydrogen/manganese system (H 2 / Mn), with a lower crossover rate than either vanadium or bromine, and even if there is crossover the manganese is inert to the Pt catalyst. 15 As a consequence, both the RHVFC and H 2 / Mn FC exhibit better durability than the H 2 /Br 2 RFC. 44,45 The rst hydrogen/benzoquinone (H 2 /BQ) system was reported by Harvard researchers with a reasonable power density of 35 mW cm À2 but cycling durability was not investigated.…”

“…[11][12][13][14] However, vanadium is a rare element so the capital cost of the redox material is a big obstacle for the large-scale commercialisation of the VRFB. [15][16][17][18][19] The energy cost of a VRFB is $320 per kW h whilst the target set by the U.S. Department of Energy (DOE) is $100 per kW h, with almost 50% of the price being dominated by the cost of the electrolyte. 20,21 In response to the price sensitivity of vanadium, various redox-active species have been investigated and suitable ones tailored to lower the cost of RFB redox materials.…”

“…49 In this investigation, we report the coupling of the BQDS positive electrolyte as reported in the literature with the hydrogen system following our investigations on the RHVFC and Mn/H 2 RFCs. 15,16 The objective of this study is to determine practical operating conditions for not only achieving decent power densities for the H 2 /BQDS system but also determining the system's cycling capabilities at a range of current densities.…”

Vanadium–Manganese Redox Flow Battery: Study of MnIII Disproportionation in the Presence of Other Metallic Ions

“…It is hypothesized that a dinuclear complex is formed between Ti IV and Mn III , protecting it from disproportionation. However, no clear spectroscopic signature has been reported so far …”

“…Recently, a hydrogen/manganese hybrid RFB has demonstrated interesting results, maintaining 75 % energy efficiency over 160 cycles at low Mn II and Ti IV concentrations to prevent MnO 2 formation (0.2 m ). However, electrolyte rebalancing was performed every five cycles to maintain stable performances . Most recently, Park et al.…”