The rapid expansion of renewable electricity is increasing the need for safe, scalable, and low-cost storage technologies. Aqueous redox flow batteries are attractive because their external tanks and electrochemical stacks enable flexible system design, easier thermal management, and modular maintenance. Among them, aqueous Zn-based flow batteries are promising because zinc is abundant and low-cost, while Zn/Zn 2+ or zincate/Zn chemistry provides a high-capacity negative electrode that can pair with iodide, bromide, iron, manganese, and other catholytes.
However, Zn-based flow batteries are not simple variants of fully soluble redox systems. In many designs, part of the energy is stored as plated metallic Zn inside the reactor, making capacity depend on deposition area, pore space, Zn morphology, and reactor geometry. Nonuniform Zn deposition, hydrogen evolution, passivation, dead-Zn formation, active-species crossover, water migration, and electrolyte imbalance can interact during cycling and standby, accelerating performance decay under practical conditions.
The review organizes recent progress into two connected directions. For Zn-anode stabilization, it discusses electrolyte regulation, artificial interphases and functional layers, and porous-electrode architectures that guide Zn nucleation and improve deposition-space utilization. For crossover and shuttle mitigation, it highlights chemistry-side regulation of active species and membrane/separator designs that balance selectivity, conductivity, mechanical stability, and long-term electrolyte balance. The authors emphasize that these approaches should be evaluated together because one improvement can introduce new trade-offs in another part of the cell.
Looking forward, the review calls for a shift from single-component optimization to integrated materials and reactor engineering. Future studies should benchmark cells under high areal capacity, high electrolyte utilization, long-duration forced-flow cycling, and dynamic current profiles. Strategies inspired by static cells should be validated in recirculating and stack-relevant configurations. Reliable state-of-charge and state-of-health diagnostics, beyond cell voltage alone, will also be important for tracking hidden degradation and avoiding electrolyte imbalance.
This review provides a practical framework for understanding degradation in aqueous Zn-based flow batteries and for designing more durable, high-energy-density systems for long-duration grid storage.
The review has been recently published in the online edition of Materials Futures, a prominent international journal in the field of interdisciplinary materials science research.
Citation: Zhiquan Wei, Dedi Li, Xinru Yang, Yiqiao Wang, Qingshun Nian, Shixun Wang, Chunyi Zhi. Advancements for aqueous Zn-based flow batteries: challenges and perspectives[J]. Materials Futures , 2026, 5(4): 042102. DOI: 10.1088/2752-5724/ae7e99
Materials Futures
Advancements for aqueous Zn-based flow batteries: challenges and perspectives
27-Jul-2026