Soluble lead flow batteries (SLFBs), a potential form of large-scale energy storage, are currently facing the challenge of short cycle life. We previously demonstrated that by adding sodium acetate (NaOAc) in the electrolyte, the life span of SLFBs can be significantly extended. Here, we aim to elucidate the effect of acetate additive on SLFBs. We find that the mechanical strength of the PbO₂ layer plated by acetate-assisted electrolyte is materially enhanced. Through electron back-scattering diffraction, certain preferred orientations of deposited PbO₂ are observed when plated without acetate additive, while random orientations are better preserved when plated with acetate additive. Via Brunauer–Emmett–Teller measurements, we find that porosity and surface area are both comparatively smaller in the acetate-assisted PbO₂ deposits, while the rate of oxygen evolution reaction (OER) is shown to be drastically reduced on PbO₂ plated with NaOAc-assisted electrolyte. We further propose that the OER pathway is suppressed by the additive due to acetate-ion adsorption at superficial PbO₂ sites, and in turn facilitates PbO₂ plating. These further discoveries are of critical value for further extending cycle life and enabling SLFB technology.

中文翻译：

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醋酸盐添加剂对可溶性铅制流动电池中PbO ₂镀层和氧释放的影响

可溶性铅流电池（SLFB）是大规模储能的一种潜在形式，目前正面临着循环寿命短的挑战。我们先前证明，通过在电解质中添加乙酸钠（NaOAc），可以显着延长SLFB的寿命。在这里，我们旨在阐明乙酸盐添加剂对SLFB的影响。我们发现，醋酸盐辅助电解质镀的PbO ₂层的机械强度得到了实质性的提高。通过电子反向散射衍射，沉积的PbO _2的某些优选取向在不添加醋酸盐添加剂的情况下进行电镀时，可以观察到这种现象；而在镀有醋酸盐添加剂的情况下，可以更好地保留随机取向。通过Brunauer-Emmett-Teller测量，我们发现，在乙酸盐辅助的PbO ₂沉积物中孔隙率和表面积均相对较小，而在镀有NaOAc的PbO ₂上，氧放出反应（OER）的速率显着降低了。辅助电解质。我们进一步提出，由于乙酸离子在浅层PbO ₂位点上的吸附，添加剂抑制了OER途径，进而促进了PbO _2的镀覆。这些进一步的发现对于进一步延长循环寿命和实现SLFB技术具有至关重要的价值。