Spinels-structured cobalt-based transition metal mixed oxides (MCo2O4): evolutionary materials for advanced supercapatteries
摘要
Supercapatteries based on the expertise of hybridizing the better qualities of both supercapacitors and batteries, are promptly becoming one of the most promising renewable and sustainable energy storage and conversion systems at global level. Efforts are being made to club the unique benefits of supercapacitors such as high-power density, fast charging rate, long-term cycling stability, and low maintenance charges with that of the high energy densities of the batteries to become a stand-alone device for a steadfast, uninterrupted power supply. It is widely known that the electrochemical performances of these energy storage systems are intimately associated with the morphology and exposed electroactive surface of the electrode materials. Consequently, worldwide researchers are focused on designing and fabricating smart, diligent electrode materials with novel shapes, morphologies to offer large surface area, superior charge transport with substantial mechanical tenacity for supporting wearable and flexible electronics. Spinel structured MCo2O4 type of mixed transition metal oxides, which have been widely popular as potential battery-type materials have recently captivated enormous research interests for modifying them as capable electrode materials for supercapatteries owing to their integral advantages of commanding theoretical capacity, eco-friendliness, natural abundance, and cost-effectiveness. Nonetheless, as far as practical applications are concerned, the MCo2O4 electroactive systems still considerably suffer from some major challenges like, inferior conductivity, relatively low observed specific capacity, along with substandard durability and therefore, the current research is targeted in narrowing the gap between the attained and theoretical capacity, without compromising with the required mass loading of electroactive materials. Thus, a comprehensive discussion on the recent advancements of MCo2O4-based nanomaterials is enormously needed to perceive as well as realize the prospects and challenges of implementations of such potential electroactive material in this fast-progressing technological sector. In this work, a basic discussion on the general criteria for developing supercapatteries have been placed as well, which will guide in realizing the necessary procedures urged to promote easy fabrication as well as better electrochemical performances of MCo2O4-based electrode materials for this emerging technology.
Graphical abstract