A cost-effective alkaline polysulfide-air redox flow battery enabled by a dual-membrane cell architecture

Abstract

With the rapid development of renewable energy harvesting technologies, there is a significant demand for long-duration energy storage technologies that can be deployed at grid scale. In this regard, polysulfide-air redox flow batteries demonstrated great potential. However, the crossover of polysulfide is one significant challenge. Here, we report a stable and cost-effective alkaline-based hybrid polysulfide-air redox flow battery where a dual-membrane-structured flow cell design mitigates the sulfur crossover issue. Moreover, combining manganese/carbon catalysed air electrodes with sulfidised Ni foam polysulfide electrodes, the redox flow battery achieves a maximum power density of 5.8 mW cm−2 at 50% state of charge and 55 °C. An average round-trip energy efficiency of 40% is also achieved over 80 cycles at 1 mA cm−2. Based on the performance reported, techno-economic analyses suggested that energy and power costs of about 2.5 US$/kWh and 1600 US$/kW, respectively, has be achieved for this type of alkaline polysulfide-air redox flow battery, with significant scope for further reduction.

Development of Membranes and Separators to Inhibit Cross‐Shuttling of Sulfur in Polysulfide‐Based Redox Flow Batteries: A Review

“…The most conventional groups necessitated for anion-conducting groups in AEMs are quaternized ammonium ions because of their facile synthesis method of treating the polymer precursors bearing benzyl halide groups with trimethylamine (TMA), as depicted in chemical structures (31)(32)(33)(34)(35)(36)(37)(38). [80][81][82][83][84] The low tolerance of AEMs to alkaline environments is considered the main drawback for advanced development and commercialization because of the hydrolysis of quaternary ammonium to hydroxyl groups.…”

“…PSA RFBs pose two key challenges: (i) the development of electrocatalysts for polysulfide redox reactions and oxygen evolution/reduction reactions, and (ii) the crossover of polysulfides across membranes or separators. [33] Wei et al ( 2016) proposed a new ferri/ferrocyanidepolysulfide (Fe/S) flow battery based on an active redox couple of alkali metal ferri/ferrocyanide and polysulfides. Graphite felt was coated with cobalt NPs, which functioned as catalysts on the polysulfide side to improve the slow kinetics of the polysulfide couple.…”

Pathways to High-Power-Density Redox Flow Batteries

“…Power density versus open-circuit voltage of selected chemistries reported in the literature. − The size and color of the circle next to each chemistry represent the state of the charge and the temperature employed, respectively.…”

Hierarchical Nano-Electrocatalytic Reactor for High Performance Polysulfides Redox Flow Batteries

“…These observations inspired us to design an advanced porous electrode current collector with highly efficiency electrocatalytic performances especially for those redox couples with sluggish electrochemical reactions. − For example, S x 2– /S 2– is an Earth-abundant redox couple to construct low cost energy storage batteries, such as lithium–sulfur batteries and aqueous redox flow batteries. − Aqueous polysulfides (S x 2– , x = 1–4) with high solubility, low molecular weight, and multielectron redox couple ensure high volumetric and mass capacity of the large-scale aqueous polysulfide RFBs. However, the sluggish conversion and mass diffusion process of S 2– /S x 2– on conventional electrodes retarded electrochemical kinetic behaviors .…”