Advancements for aqueous Zn-based flow batteries: challenges and perspectives

Aqueous Zn-based flow batteries (FBs) have emerged as a promising technology for large-scale, long-duration energy storage owing to their inherent safety, low-cost Zn resources, and high-capacity Zn-anode chemistry. These advantages make Zn-based FBs particularly attractive for grid-scale integration of renewable energy. However, their practical deployment and commercialization are still hindered by coupled degradation processes, especially Zn-anode reversibility loss and active-species crossover/shuttle under realistic operating conditions. This review provides a focused overview of failure mechanisms and recent mitigation strategies in aqueous Zn-based FBs. The key challenges associated with non-uniform Zn deposition/stripping, parasitic reactions, and crossover/shuttle are discussed, together with recent advances in electrolyte regulation, electrode-architecture design, chemistry-side crossover control, and membrane/separator engineering. The coupling and trade-offs among interfacial stability, transport selectivity, ionic conductivity, and full-cell performance are also highlighted. Future research directions are finally suggested to focus on practical-condition benchmarking, forced-flow validation of strategies developed in static cells, reliable charge-state and health-state diagnostics and control, and the development of truly flowable Zn-containing energy reservoirs for achieving practical Zn-based FBs. © 2026 The Author(s). Published by IOP Publishing Ltd on behalf of the Dongguan Institute of Materials Science and Technology, CAS. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.