LAUSR

Redox flow batteries (RFBs) are a highly promising large-scale energy storage technology for mitigating the intermittency nature of renewable energy sources. Here, we report the design and implementation of a micellization strategy in an anthraquinone-based, pH-neutral, nontoxic, metal-free, aqueous RFB. The micellization strategy (1) improves stability by protecting the redox-active anthraquinone core with a hydrophilic poly(ethylene glycol) shell; and (2) increases the overall size to mitigate the crossover issue via a physical blocking mechanism. Paired with a well-established potassium ferrocyanide catholyte, the micelle-based RFB displayed an excellent capacity retention of 90.7% after 3600 charge/discharge cycles (28.3 days), corresponding to a capacity retention of 99.67% per day and 99.998% per cycle. The mechanistic studies of redox-active materials were also conducted and indicated the absence of side reactions that were commonly observed in other anthraquinone-based RFBs. The outstanding performance of the RFB demonstrates the effectiveness of the micellization strategy for enhancing the performance of organic material-based aqueous RFBs.