Long duration energy storage (LDES) technologies are vital for wide utilization of renewable energy sources and increasing the penetration of these technologies within energy infrastructures. Herein, we propose a low-cost alkaline all-iron flow battery by coupling ferri/ferro-cyanide redox couple with ferric/ferrous-gluconate complexes redox couple. The designed all-iron flow battery demonstrates a coulombic efficiency of above 99% and an energy efficiency of ∼83% at a current density of 80 mA cm −2 , which can continuously run for more than 950 cycles. Most importantly, the battery demonstrates a coulombic efficiency of more than 99.0% and an energy efficiency of ∼83% for a long duration (∼12, 16 and 20 h per cycle) charge/discharge process. Benefiting from the low cost of iron electrolytes, the overall cost of the all-iron flow battery system can be reached as low as $76.11 per kWh based on a 10 h system with a power of 9.9 kW. This work provides a new option for next-generation cost-effective flow batteries for long duration large scale energy storage.
Hybrid flow batteries are one of the most promising technologies for storing the electricity generated from intermittent renewables , such as wind and solar. However, most of the existing hybrid systems currently suffer from low power density and poor cycle performance resulted from the parasitic reactions. To mitigate these issues, here we report a tin-iron hybrid flow battery in which the stannous chloride anolyte is separated from the ferric/ferrous chloride catholyte. With the reversible tin metal deposition/stripping and ferric/ferrous chloride redox reactions at carbon surfaces , the present battery delivers an energy efficiency of 78.5% even at the current density of 200 mA cm −2 . In addition, owing to high hydrogen overvoltage of metallic tin, the parasitic hydrogen evolution reaction in the negative electrode can be largely avoided so that the battery can stably operate over 700 cycles without obvious efficiency decay. With the excellent rate and cycle performance, it is envisioned that the tin-iron flow battery is a promising candidate for large-scale energy storage applications .
危险品化学品经营许可证（带存储）