Recent advances in the development, design and mechanism of negative electrodes for asymmetric supercapacitor applications

Abstract

Continuous technical advancements in a variety of industries, such as portable electronics, transportation, green energy, are frequently hampered by the inadequacy of energy-storage technologies. Asymmetric supercapacitors can expand their operating voltage window past the thermodynamic breakdown voltage of electrolytes by utilizing two distinct electrode materials, providing a workaround for the symmetric supercapacitors’ energy storage constraints. This evaluation offers a thorough understanding of this area. To comprehend the extensive research done in this field, we first examine the fundamental energy-storage mechanisms and performance evaluation standards for asymmetric supercapacitors. The most recent developments in the design and manufacture of electrode materials as well as the general structure of asymmetric supercapacitors. We have also discussed a number of significant scientific issues and offer our opinions on how to improve the electrochemical properties of future asymmetric energy storage devices. First, methods for designing high-performance electrode materials for supercapacitors must be developed; next, controllably built supercapacitor types must be attained (such as symmetric capacitors including double-layer and pseudocapacitors, asymmetric capacitors, and Li-ion capacitors). This review is timely because of the rapid expansion of research in this area. It summarizes recent developments in the study and creation of high-performance electrode materials with high supercapacitors. A number of crucial topics for enhancing the energy density of supercapacitors are examined, along with some reciprocal correlations between the main impacting parameters. Difficulties and prospects in this fascinating field are also covered. This offers a fundamental understanding of supercapacitors and serves as a crucial design rule for enhanced next-generation supercapacitors that will be used in both industrial and consumer applications. In this context, we extensively reviewed the classification of supercapacitor, EDLC (activated carbon, carbon aerogel, carbon nanotube), Pseudocapacitors, conducting polymers, metal oxides, hybrid materials, composite hybrids, rechargeable batteries, asymmetric devices and its design, aqueous solid state, fiber based asymmetric device, graphene based asymmetric device, terminologies used during the electrode selection, positive and negative electrodes in asymmetric device, material used for fabrication of negative electrodes, electrochemical performance of various devices which are fabricated by different electrode materials. Performance of material for various asymmetric device applications, conclusions outlook, recent developments in asymmetric devices. The current review may offer a thorough understanding and future prospects for developing negative electrodes to enhance asymmetric supercapacitor performance.