Chinese scientists announced a breakthrough in stationary energy storage systems. A team led by Professor Li Xianfeng from the Dalian Institute of Chemical Physics CAS unveiled a novel zinc-bromine flow battery featuring unprecedented operational stability. Its foundation lies in an innovative two-electron transfer scheme for bromine, which fundamentally alters this element’s behavior within the cell.
Traditional zinc-bromine setups suffer from one major drawback: elemental bromine accumulates in the electrolyte during charging. This substance is highly corrosive, degrading electrodes, current collectors, and membranes, which rapidly depletes the lifespan and renders such batteries costly and hazardous. Chinese researchers proposed a fundamentally different method—to “tether” the free bromine right during operation.
Specially selected amine compounds were introduced into the electrolyte. They react with the bromine, transforming it not into aggressive free element, but into brominated amines. Consequently, the concentration of elemental bromine in the solution remains ultra-low, and the system’s corrosive activity sharply declines. This simultaneously boosts safety and significantly extends the battery’s service duration.
Thanks to this operational mode, it became viable to employ a standard non-fluorinated ion-exchange membrane—without the expensive, ultra-resistant materials typically necessitated by bromine systems. This directly lowers installation expense and simplifies technology scaling.
In trials of a 5 kW flow system, the battery displayed remarkable stability: over 700 operating cycles at a current density of 40 mA/cm² with an energy efficiency exceeding 78%. Post-test analysis of the electrodes, current collectors, and membrane revealed no signs of erosion. The developers believe this architecture paves the way for crafting durable, safe, and cost-effective energy accumulators for power grids and renewable sources.
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