We demonstrate a long-lifetime, aqueous redox-flow battery that can operate at a pH as low as 12 while maintaining an open-circuit voltage of over 1 V. We functionalized 2,6-dihydroxyanthraquinone (2,6-DHAQ) with highly alkali-soluble carboxylate terminal groups. The resulting negative electrolyte material 4,4′-((9,10-anthraquinone-2,6-diyl)dioxy)dibutyrate (2,6-DBEAQ) was six times more soluble than 2,6-DHAQ at pH 12. Symmetric cell cycling with 2,6-DBEAQ on both sides of the cell demonstrates a capacity fade rate of <0.01%/day and <0.001%/cycle. By pairing 2,6-DBEAQ with a potassium ferri-/ferrocyanide positive electrolyte and utilizing a non-fluorinated membrane, this near-neutral flow battery shows a capacity fade rate that is the lowest of any quinone and rivals the lowest ever reported for any flow battery in the absence of rebalancing processes. This result adds the important attribute of long calendar life to quinone-based redox-flow batteries, which may enable massive penetration of intermittent renewable electricity.

我们展示了一种长寿命的水性氧化还原液流电池，该电池可以在低至12的pH值下工作，同时保持超过1 V的开路电压。我们将2,6-二羟基蒽醌（2,6-DHAQ）高度官能化。碱溶性羧酸盐端基。所得负电解质材料4,4'-（（（9,10-蒽醌-2,6-二基）二氧基）二丁酸）二丁酸酯（2,6-DBEAQ）在pH 12时的溶解度是2,6-DHAQ的六倍。在电池两边使用2,6-DBEAQ进行的电池循环显示容量衰减率<0.01％/天和<0.001％/循环。通过将2，6-DBEAQ与亚铁氰化钾/亚铁氰化钾正电解质配对并利用非氟化膜，在没有重新平衡过程的情况下，这种接近中性的液流电池的容量衰减率是所有醌中最低的，可与任何液流电池中所报道的最低值相媲美。该结果为基于醌的氧化还原液流电池增加了长日历寿命的重要属性，这可以使间歇性可再生电力大量渗透。