A Stable Vanadium Redox‐Flow Battery with High Energy Density for Large‐Scale Energy Storage

TLDR

All‑vanadium redox flow batteries are promising for large‑scale renewable and grid storage, yet their low energy density and electrolyte instability limit performance. The study reports a new vanadium redox flow battery that significantly improves upon current technology. The battery employs sulfate‑chloride mixed electrolytes that dissolve 2.5 M vanadium, boosting energy capacity by ~70 % over conventional sulfate systems. The electrolyte remains stable from −5 to 50 °C, eliminating temperature‑control needs and potentially reducing energy‑storage costs to accelerate market penetration.

Abstract

Abstract The all‐vanadium redox flow battery is a promising technology for large‐scale renewable and grid energy storage, but is limited by the low energy density and poor stability of the vanadium electrolyte solutions. A new vanadium redox flow battery with a significant improvement over the current technology is reported in this paper. This battery uses sulfate‐chloride mixed electrolytes, which are capable of dissolving 2.5 M vanadium, representing about a 70% increase in energy capacity over the current sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of −5 to 50 °C, potentially eliminating the need for electrolyte temperature control in practical applications. This development would lead to a significant reduction in the cost of energy storage, thus accelerating its market penetration.