Redox flow batteries: Asymmetric design analysis and research methods

The decoupling of energy and power in a redox flow battery (RFB) renders it a suitable candidate for large-scale energy storage. However, the performance of RFB is typically influenced by a number of factors, including limited solubility, active material crossover, and disparities in positive and negative dynamics. Moreover, symmetrical RFB typically exhibit low energy density and face significant challenges in reducing the differences between positive and negative electrodes. It is therefore imperative that the adoption of asymmetric RFB be pursued as a means of addressing the issues and challenges inherent in the symmetric RFB framework. To address these issues, it is important to investigate the development of asymmetric RFB and extract the creation of an asymmetric RFB with a higher energy density and more balanced positive and negative dynamics. This review provides a comprehensive analysis of the recent research advancements in asymmetric electrolytes, operational techniques, and electrodes. Furthermore, it explores the utilization of asymmetry to address challenges and its profound impact on enhancing battery performance. Finally, the improvement of battery performance by asymmetric temperature is discussed. The objective of this review is to offer a point of reference for enhancing the performance of RFB through the utilization of asymmetric research methods.