Highly reliable alkaline zinc-based flow batteries are promising options for stationary energy storage and require uniform zinc plating determined by anolyte chemistry. However, the anolyte properties, particularly molecular structure of zincate ion are intricate and yet to be clearly identified. Herein, we report a N, N, N′ N′-Tetra(2-hydroxyethyl) ethylenediamine (THEED) additive to enable uniform zinc plating by altering molecular structure of zincate couple. The THEED can complex with Zn(OH)₄^2- and form Zn(OH)_x^x−2-THEED-H₂O with slow-down deposition kinetics on anode and realizing uniform plating of zinc, and form new hydrogen bond networks with water, favoring trapping water molecules. These in turn enable alkaline zinc-iron flow battery single cell and cell stack with dramatically improved reliability. Additionally, the THEED could suppress the migration of water during charge/discharge process. This work illustrates new ways for realizing uniform zinc plating based on scientific understanding of electrolyte chemistry to promote the development of alkaline zinc-based flow batteries.

高度可靠的碱性锌基液流电池是固定式储能的有前途的选择，并且需要由阳极液化学确定的均匀镀锌层。然而，阳极电解液的性质，特别是锌酸根离子的分子结构是复杂的，尚待明确鉴定。在此，我们报道了一种 N, N, N' N'-四 (2-羟乙基) 乙二胺 (THEED) 添加剂，通过改变锌酸盐对的分子结构来实现均匀的镀锌。THEED可以与Zn(OH) ₄ ^2-络合形成Zn(OH) _x ^x−2 -THEED-H ₂O在阳极上的沉积动力学减慢，实现锌的均匀镀层，并与水形成新的氢键网络，有利于捕获水分子。这些反过来又使碱性锌铁液流电池单节电池和电池组具有显着提高的可靠性。此外，THED 可以抑制充电/放电过程中水的迁移。这项工作阐明了基于对电解质化学的科学认识实现均匀镀锌的新途径，以促进碱性锌基液流电池的发展。