Assessing the Effect of Stabilization and Carbonization Temperatures on Electrochemical Performance of Electrospun Carbon Nanofibers from Polyacrylonitrile

Abstract

Supercapacitors (SCs) are considered a promising alternative to batteries to power up portable and wearable devices. Among different categories of materials for SCs, carbon nanofibers (CNFs) are particularly appealing for their electrochemical, morphological, and mechanical properties, coupled with the ease of synthesis. Electrospinning is a simple and low‐cost technique to prepare the polymer‐based precursors for CNFs, allowing to obtain fibers with a tunable morphology and a diameter in the nanometer range. However, even if electrospun CNFs were intensely studied over the years, in the literature there is a lack of information regarding the optimization of the thermal treatment to prepare bare CNFs with high specific capacitance (C s). Herein, a systematic study on the optimization of the stabilization and carbonization temperatures for electrospun CNFs prepared from polyacrylonirtile is reported, achieving a maximum C s of 49 F g−1 at 0.5 A g−1 in a symmetrical SC device based on 1 m H2SO4 electrolyte. Aspects related to the specific surface area, nitrogen doping, and carbon microstructure are examined concerning the different thermal treatments, allowing to define structure–property–function relationships in these capacitive nanoarchitectures.

Multicomponent Synergistic Contribution in Nanoengineered Nanofibers for Flexible Energy Storage

“…Here, our material performs better than or comparably to several published examples. From carbon-based materials, there are also works, especially in the field of CNFs, reporting larger C s : in our previous work on CNFs, we reached 49 F g –1 at 0.5 A g –1 , while in other examples activated CNFs provided 83.3 F g –1 at a current density of 100 mA g –1 or 95 F g –1 at a scan rate of 10 mV s –1 . ,, However, it is worth noting that most CNF-based electrodes have limited flexibility, which makes them unsuitable for application in flexible energy storage devices.…”

“…However, CNFs, for instance, are mainly produced from polyacrylonitrile or polyvinylpyrrolidone, where toxic solvents like N , N -dimethylformamide and tetrahydrofuran have to be used for preparation. Furthermore, large temperatures up to 900 °C under a reducing atmosphere are commonly used to produce them. , Also for exfoliation of TMDs, toxic solvents are generally used, being N -methylpyrrolidone the most prominent example. − However, also nontoxic solvents can be employed for both fiber production and for the exfoliation of TMDs. To adhere as much as possible to green methods, ethanol, isopropanol (IPA), and water are good choices of liquid media for processing …”