Ion-Regulating Membranes with Surface-Enriched Charge Networks Enabling Stable Zinc-Manganese Flow Batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41387376.
- Also identified by DOI 10.1002/adma.202517473 and PMC identifier 12902590.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Zinc-based flow batteries are promising for sustainable energy storage owing to their high energy density and eco-friendliness. When coupling with Mn<sup>2+</sup>/MnO<sub>2</sub> posolyte, the zinc-manganese flow batteries promise an ultra-low electrolyte cost (0.0039 $ Ah<sup>-1</sup>). However, their practical application is limited by low areal capacity (<20 mAh cm<sup>-2</sup>) and poor lifespan (<100 cycles with accumulated capacity < 2000 mAh cm<sup>-2</sup>), associated with proton crossover and zinc dendrite formation. To address the two bottlenecks, an ion-regulating membrane with surface-enriched positive charges of Zn<sup>2+</sup> crosslinked networks is proposed. The enriched-charged networks amplify H⁺ retention (60% elevated proton transport barrier to 0.104 eV) via imposing charge-enhanced dehydration barriers and nitrogen-groups synergism, leveraging the higher ionic potential of protons to discriminate the conduction ions (K<sup>+</sup>). Simultaneously, the surface charges electrostatically guide the uniform distribution of near-electrode zinc ions for zinc-oriented growth without dendrites. The synergistic strategy achieves a near-neutral zinc-manganese flow system with a record accumulated capacity of 6510 mAh cm<sup>-2</sup> (>200 cycles) at 30 mA cm<sup>-2</sup>, high areal capacity of 100 mAh cm<sup>-2</sup> (130.1 mWh cm<sup>-2</sup>) at 20 mA cm<sup>-2</sup>, representing one of the most stable zinc-manganese flow batteries reported. This study provides an effective membrane design strategy for low-cost and high-energy-density zinc-based flow batteries.