Fabrication of highly porous cobalt oxide decorated carbon nanofibers for supercapacitors applications

Abstract

It is evident that fossil fuels have led to incredible advancements in our life. However, their exhaustion has badly affected our environment by generating greenhouse gases and increasing air pollution. This is why nowadays, there is an urgent demand on green energy. This latter can be obtained from different sources coming from wind, solar power, etc. For sure these sources are abundant and for free, however, storing the energy coming from them to be used where and when needed is the issue. There exist several types of energy storage devices, where supercapacitors (SCs) are one of the most commonly used. SCs are known to have high power density, fast charge-discharge, and long cycle life. Despite all these advantages, their high cost of manufacturing and low energy density limit their commercialization. Many efforts have been made to resolve these problems by developing novels materials that can be cheap and can deliver high energy density while keeping good stability. Hybrid porous carbon nanofibers (CNFs) doped with metal oxides are one of the systems found to satisfy these characteristics when used as electrodes for SCs. In this study, a free-standing hybrid nanomaterial “Cobalt oxide doped CNFs” was made from a biopolymer “corn starch” by means of a cost-effective and scalable technique “electrospinning”. A subsequent immersion in cobalt acetate solution was proceeded in order to introduce cobalt into CNFs, followed by a final calcination to get $Co_3O_4$ nanoparticles. The obtained hybrid nanofibers exhibit highly porous microstructure with a suitable pore size distribution. This facile dip-coating process led to formation of $Co_3O_4$ which further enhanced the electrochemical properties of the hybrid nanofibers such as specific capacitance and discharge time, and contributed to a good stable cycle life.