Toward Dendrite-Free Deposition in Zinc-Based Flow Batteries: Status and Prospects

Safe and low-cost zinc-based flow batteries offer great promise for grid-scale energy storage, which is the key to the widespread adoption of renewable energies. However, advancement in this technology is considerably hindered by the notorious zinc dendrite formation that results in low Coulombic efficiencies, fast capacity decay, and even short circuits. In this review, we first discuss the fundamental mechanisms of zinc dendrite formation and identify the key factors affecting zinc deposition. Then, strategies to regulate zinc deposition are clarified and discussed based on electrode, electrolyte, and membrane. The underlying mechanisms, advantages, and shortcomings of each strategy are elaborated. Finally, the remaining challenges and perspectives of zinc-based flow batteries are presented. The review may provide promising directions for the development of dendrite-free zinc-based flow batteries.