Unleashing capabilities of supercapacitors: Strategies to reduce internal resistances

Facing the requirements of energy conversion and storage, the future design of supercapacitors (SC) should achieve higher energy and power densities, which requires SC to have lower internal resistance to realize the best electrochemical performance. Therefore, exploring different measures to reduce the system's internal resistance is crucial for the future development of SC. In this paper, based on the composition of SC and the diffusion process of ions in SC, some effective strategies to reduce the internal resistance are discussed by analyzing the composition and cause of internal resistance of SC. Including the interface engineering between components and the optimization design method of electrodes, electrolytes, and diaphragms to realize the rapid transport of ions at the interface and inside the components are discussed. At the same time, the technical challenges, and future prospects of the strategy to reduce internal resistance in SC design are prospected from different perspectives. This review can provide fresh ideas and directions for the future development of SCs with lower internal resistance and higher performance.