摘要
Redox flow batteries represent a leading platform for long-duration stationary energy storage; however, aqueous systems are constrained by the narrow stability window of water, which limits operating voltage and practical energy density. Nonaqueous redox flow batteries (NRFBs) expand the accessible potential window and enable organic redox-active molecules to achieve cell voltages above 2 V. This review analyzes molecular strategies that facilitate high-potential operation in nonaqueous media, with emphasis on the coupled requirements of redox potential, solubility at deployment-relevant concentrations, and long-term reversibility of charged states. The redox-potential landscape of major organic scaffolds is mapped, relating functional-group tuning, steric protection, and resonance delocalization to high-voltage stability. Solubility-enhancing modifications are examined, and their practical consequences for viscosity, diffusion, conductivity, and crossover are assessed using available literature data. Full-cell demonstrations are assessed to identify bottlenecks and outline research priorities, including standardized benchmarking, molecule-separator co-design, and modeling-assisted screening that links redox energetics with transport and degradation descriptors. © 2026 Elsevier Ltd.