A Green Titanium‐Cerium Redox Flow Battery with Long‐Term Stability via Efficient Capacity Recovery

Redox flow batteries (RFBs) have emerged as a transformative technology for large‐scale energy storage, with growing research interest in developing cost‐effective and durable systems. Here, we present a capacity recoverable RFB system that utilizes low‐cost titanium/cerium species‐Ti‐Ce RFBs. A mixed‐electrolyte design suppresses ion crossover, achieving the average energy efficiency of 86.02% at 30mA cm −2 . Moreover, owing to the few side reaction and unique active ion complex structure with negative or neutral charge, the capacity of Ti‐Ce RFBs after attenuation can be almost completely recovered by directly mixing the electrolyte. Remarkably, exceptional long‐term stability over 3721 cycles (1886 h) at 50 mA cm −2 with average coulombic efficiency of 99.09% can be achieved by recovery regulation of mixing the electrolytes after attenuation. This design offers a simple but practical strategy to make Ti‐Ce RFBs as a promising candidate for long‐duration energy storage.