Enhanced Performance of Zn/Br Flow Battery Using N-Methyl-N-Propylmorpholinium Bromide as Complexing Agent

Back to the future with emerging iron technologies

Here is a comprehensive overview of iron's potential in low-carbon energy technologies, exploring applications like metal fuel combustion, iron-based batteries, and energy-carrier cycles, as well as sustainable approaches for production and recycling with a focus on reducing environmental impact. Iron, with its abundance, safety, and electrochemical characteristics, is a promising material to contribute to a decarbonized future. This paper discusses the advancements and challenges in iron-based energy storage technologies and sustainable iron production methods. Various innovative approaches are explored as energy storage solutions based on iron, like advancements in thermochemical Fe-Cl cycles highlight the potential of iron chloride electrochemical cycles for long-term high-capacity energy storage technology. Additionally, the utilization of iron as a circular fuel in industrial processes demonstrates its potential in large-scale thermal energy generation. Sustainable iron production methods, such as electrolysis of iron chloride or oxide and deep eutectic solvent extraction, are investigated to reduce the carbon footprint in the iron and steel industry. These findings also show the importance of policy and technology improvements that are vital for the widespread use and recycling of iron-based tech, stressing the need for collaboration toward a sustainable future.

Rational Design Toward Advanced Non-Flow Aqueous Zinc-Bromine Systems Boosted by Alkaline-Neutral Decoupling Electrolytes

Non-flow aqueous zinc-bromine batteries (AZBBs) are highly attractive owing to their lightweight construction and largely reduced cost compared with the flow ones. Yet, their development is restricted by the sluggish reaction kinetics of Br2/Br-, the shuttle of soluble polybromide species (Brn -, n is odd), and the poor stability of Zn-based anode. Herein, an effective alkaline-neutral electrolyte decoupling system is constructed to mitigate these issues, where nitrogen-doped carbon felt with high catalytic activity to Br2/Br- reaction is developed for cathode, a cost-effective cation exchange membrane (CEM) of polyethersulfone/sulfonated polyether ether ketone (PES/SPEEK-M) that can stop Brn - is used as separator, and glucose that can inhibit dendrites is introduced as anolyte additive. The constructed flowless AZBB mainly consists of two separate redox couples, including Zn/Zn(OH)4 2- in alkaline anolyte and Br2/Br- in neutral media, where non-cations (e.g. OH-, Zn(OH)4 2-, H2O,  and Brn -) can be restricted to their respective chamber by the PES/SPEEK-M while cations can pass by. In the optimized system, good electrochemical performance is achieved, mainly including a surprising discharge voltage of 2.01 V, a high average Coulombic efficiency of 96.7%, and a good cycling life of ≈1000 cycles without obvious capacity decay at a fixed charge capacity of 2 mAh cm-2.