Eutectic electrolyte and interface engineering for redox flow batteries

Eutectic electrolytes based redox flow batteries (RFBs) are acknowledged as promising candidates for large-scale energy storage systems on account of low cost and high energy density. However, how to develop high-performance eutectic electrolytes (including low viscosity and sufficient conductivity) and compatible interfaces for constructing eutectic-based RFBs are still challenging that need to be overcome before their commercialization. In this review, we mainly focus on the eutectic electrolytes and their interfaces for redox flow batteries. The transport theory is first discussed. And then, the fundamental performances of eutectic electrolytes and concomitant interfacial issues in RFBs are introduced. Moreover, to address the obstacles encountered with eutectic electrolytes and interfaces, the regulations for electrolytes and modifications for interfaces are systematically summarized. Finally, perspectives on the future development of eutectic-based RFBs are also briefly anticipated. This review provides profound insights into the challenges of eutectics and interfaces for the next-generation RFBs.