Advancement in Supercapacitors: Breaking Barriers and Shaping into Amazing Applications

Supercapacitors (Scs) displayed intrinsic advantages such as high-power density and high-rate capability but lower energy density. The development of advanced pseudocapacitive electrode materials is crucial for advancement in supercapacitor technologies. Such electrode materials significantly influence the performance of supercapacitors in electrical energy storage (EES) systems with respective energy density and cycling stabily. In this review, we first discussed, the EES technologies and their development and types of SCs, followed by overview of the importance of organic electrode materials for pseudocapacitor (PSC) applications. We also present principle of different redox-active organic molecules design strategy and their theoretical calculations in order to understand their electrochemical characteristics. Furthermore, we have highlighted redox-active organic electrode materials role in achieving wider potential voltage window and in turn higher energy density that enhance the electrochemical performance of PSCs. We have also discussed the role of molecular structure, their composition with electronic conducting materials and their structural and electrochemical performance relationship and highlighted the advantages and disadvantages of organic materials compared with traditional transition-metal oxide inorganic materials for PSCs. We give brief discussion on the advances in small redox-active molecular architecture and their use in fabrication of novel electrode materials including polymers, covalent organic frameworks and metal organic frameworks. We provided in depth how such material development from small redox-active molecules advances the charge-storage field and their applications to illuminate light emitting diodes as their application part. We are hoping this review article will help to provide fundamental basis to design and develop next-generation pseudocapacitive electrode materials from the renewable sources for sustainable supercapacitor systems with higher charge-storage capability.