Redox flow batteries (RFBs) are a promising technology for large-scale energy storage. Rapid research developments in RFB chemistries, materials and devices have laid critical foundations for cost-effective and long-lasting RFB systems. However, the lack of consistency in testing methods and assessment metrics makes it challenging to compare reported RFBs and evaluate their potential for practical applications. Here we discuss RFB assessment methods and performance metrics in direct relation to their working principles and degradation mechanisms. We first introduce basic cell attributes and performance metrics and describe common misconceptions in testing and performance comparison. We discuss major RFB decay mechanisms and highlight bottlenecks in organic, inorganic and solid-hybrid RFBs. Testing protocols, reporting practices and comparison criteria are proposed under a general framework of symmetric and asymmetric full RFBs. These recommendations can be broadly applied to a wide range of flow battery chemistries to facilitate future benchmarking and RFB development.

氧化还原液流电池（RFB）是用于大规模能量存储的有前途的技术。RFB化学，材料和设备的快速研究发展为经济高效且持久的RFB系统奠定了关键基础。但是，由于测试方法和评估指标缺乏一致性，因此很难比较已报告的RFB并评估其在实际应用中的潜力。在这里，我们讨论与RFB的工作原理和降级机制直接相关的RFB评估方法和绩效指标。我们首先介绍基本的单元属性和性能指标，并描述测试和性能比较中的常见误解。我们讨论了主要的RFB衰减机制，并重点介绍了有机，无机和固体混合RFB的瓶颈。测试协议 在对称和非对称完整RFB的一般框架下提出了报告实践和比较标准。这些建议可广泛应用于各种液流电池化学，以促进将来的基准测试和RFB开发。