With the widespread exploitations of renewable energy sources, electrochemical energy storage (EES) systems that could store electric energy in large quantity and buffer the impact of intermittently generated electricity from wind and solar, become increasingly important for the resilience and quality of power grids. Among various EES systems, redox flow batteries (RFBs) offer greater promise for reliable and durable grid-scale storage of electricity owing to their salient feature of decoupled energy storage and power generation. However, the deployments of RFBs are severely impeded by the high material and system costs. Polysulfide has been studied as a low-cost, highly soluble, and robust anodic redox species for RFBs, although it suffers from sluggish reaction kinetics. Here, we report a feasible successive ionic layer adsorption and reaction method to graft the copper sulfide electrocatalyst on the graphite felt electrode, which substantially promotes the redox reaction of polysulfide. With [Fe(CN)₆]^4−/3− as the catholyte and polysulfide as the anolyte, an RFB with a power density of 116 mW cm⁻² at 220 mA cm⁻² and an energy efficiency of 77.7% at 50 mA cm⁻² has been attained, markedly superior to the reported ones. With the considerably improved performance, the polysulfide-[Fe(CN)₆]^4−/3− flow battery has been demonstrated to be a cost-effective solution for large-scale energy storage.

随着可再生能源的广泛开发，可大量存储电能并缓冲来自风能和太阳能的间歇性发电的影响的电化学能存储（EES）系统对于电网的弹性和质量变得越来越重要。在各种EES系统中，氧化还原液流电池（RFB）由于其能量存储和发电分离的显着特征，为可靠和持久的电网规模的电力存储提供了更大的希望。但是，高昂的材料和系统成本严重阻碍了RFB的部署。尽管多硫化物的反应动力学较慢，但它已被视为一种低成本，高溶解度且坚固的RFB阳极氧化还原物质。这里，我们报道了一种可行的连续离子层吸附和反应方法，将硫化铜电催化剂接枝到石墨毡电极上，从而大大促进了多硫化物的氧化还原反应。与[Fe（CN）₆ ] ^{4- / 3-}作为阴极电解液和多硫化物作为阳极电解液，具有116毫瓦厘米的功率密度的RFB ^-2在220毫安厘米^-2和77.7％在50mA厘米的能量效率^-2 已经达到，明显优于已报道的。通过显着改善的性能，聚硫化物-[Fe（CN）₆ ] ^{4- / 3--}液流电池已被证明是用于大规模储能的经济有效的解决方案。