Hybrid and Asymmetric Supercapacitors: Achieving Balanced Stored Charge across Electrode Materials

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 33; pp. e2400558 - n/a
• Main Authors: Qorbani, Mohammad, Chen, Kuei‐Hsien, Chen, Li‐Chyong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2024
• Subjects: Asymmetry; charge balancing; Charge materials; charge–discharge current density; Configuration management; Discharge; Electrochemical analysis; electrochemical capacitor; Electrode materials; Electrodes; hybrid and asymmetric device; Methodology; rate capability; supercapacitor; Supercapacitors; sweep rate; charge–discharge current density; sweep rate; charge balancing; hybrid and asymmetric device; rate capability; electrochemical capacitor; supercapacitor
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202400558

An electrochemical capacitor configuration extends its operational potential window by leveraging diverse charge storage mechanisms on the positive and negative electrodes. Beyond harnessing capacitive, pseudocapacitive, or Faradaic energy storage mechanisms and enhancing electrochemical performance at high rates, achieving a balance of stored charge across electrodes poses a significant challenge over a wide range of charge–discharge currents or sweep rates. Consequently, fabricating hybrid and asymmetric supercapacitors demands precise electrochemical evaluations of electrode materials and the development of a reliable methodology. This work provides an overview of fundamental aspects related to charge‐storage mechanisms and electrochemical methods, aiming to discern the contribution of each process. Subsequently, the electrochemical properties, including the working potential windows, rate capability profiles, and stabilities, of various families of electrode materials are explored. It is then demonstrated, how charge balancing between electrodes falters across a broad range of charge–discharge currents or sweep rates. Finally, a methodology for achieving charge balance in hybrid and asymmetric supercapacitors is proposed, outlining multiple conditions dependent on loaded mass and charge–discharge current. Two step‐by‐step tutorials and model examples for applying this methodology are also provided. The proposed methodology is anticipated to stimulate continued dialogue among researchers, fostering advancements in achieving stable and high‐performance supercapacitor devices. Addressing the intricate challenge of charge balancing in hybrid and asymmetric supercapacitors, this work proposes a robust methodology. By outlining specific conditions dependent on loaded mass and charge–discharge current or sweep rate, it offers comprehensive insights. Explore these strategies in detail within the extensive table of contents, providing a nuanced understanding of effective charge balancing across positive and negative electrodes.