The redox flow battery (RFB) is among the most promising large-scale energy storage technologies for intermittent renewables, but its cost and cycle life still remain challenging for commercialization. This work proposes and demonstrates a high-performance, low-cost and long-life tin-bromine redox flow battery (Sn/Br RFB) with the Br-mixed electrolyte. The coulombic efficiency and energy efficiency of the Sn/Br RFB reach 97.6% and 82.6% at a high operating current density of 200 mA cm⁻², respectively. The peak power density at 50% state-of-charge achieves 673 and 824 mW cm⁻² at 15 and 35 °C, respectively, which is among the highest performance of hybrid RFBs. To address the Sn cross-contamination issue, a Sn reverse-electrodeposition method is demonstrated, and achieves in-situ capacity recovery as well as long cycle life. Moreover, the active material cost of the Br-mixed electrolyte is merely $54 kWh⁻¹, while capital cost of the Sn/Br RFB is estimated to be as low as $193 kWh⁻¹ for 4-hour electricity discharge, and expected to reduce to $148 kWh⁻¹ at the optimistic scenario in the future. With high cell performance, in-situ capacity recovery and inexpensive active materials, the Sn/Br RFB is believed to offer a promising solution for massive electricity storage.

氧化还原液流电池（RFB）是间歇性可再生能源中最有前途的大规模储能技术之一，但是其成本和循环寿命仍然对商业化提出挑战。这项工作提出并演示了一种高性能，低成本，长寿命的含溴混合电解质的锡溴氧化还原液流电池（Sn / Br RFB）。在200mA cm ^-2的高工作电流密度下，Sn / Br RFB的库伦效率和能量效率分别达到97.6％和82.6％。50％充电状态下的峰值功率密度达到673和824 mW cm ^-2分别在15和35°C的温度下工作，这是混合RFB的最高性能之一。为了解决Sn交叉污染的问题，展示了一种Sn反向电沉积方法，该方法可实现原位容量恢复以及长循环寿命。此外，Br混合电解质的活性材料成本仅为54 kWh ^-1，而Sn / Br RFB的资本成本估计为4小时放电低至193 kWh ^-1，并有望降低在未来的乐观情景下将达到$ 148 kWh ^-1。凭借高电池性能，原位容量恢复和廉价的活性材料，Sn / Br RFB被认为为大规模的电力存储提供了有希望的解决方案。