Abstract
Carbon felt (CF) is an inexpensive carbon-based material that is highly conductive and features extraordinary inherent surface area. Using such a metal-free, low-cost material for energy storage applications can benefit their practical implementation; however, only limited success has been achieved using metal-free CF for supercapacitor electrodes. This work thoroughly studies a cost-effective and simple method for activating metal-free self-supported carbon felt. As-received CF samples were first chemically modified with an acidic mixture, then put through a time optimization two-step electrochemical treatment in inorganic salts. The initial oxidative exfoliation process enhances the fiber’s surface area and ultimately introduced oxygen functional groups to the surface, whereas the subsequent reduction process substantially improved the conductivity. We achieved a 205-fold enhancement of capacitance over the as-received CF, with a maximum specific capacitance of 205 Fg−1, while using a charging current density of 23 mAg−1. Additionally, we obtained a remarkable capacitance retention of 78% upon increasing the charging current from 0.4 to 1 Ag−1. Finally, the cyclic stability reached 87% capacitance retention after 2500 cycles. These results demonstrate the potential utility of electrochemically activated CF electrodes in supercapacitor devices.
Highlights
The electrical double-layer capacitors are electrical energy storage devices that offer attractive features, such as fast storing/releasing of energy, long cycling life, and high reversibility as they combine the benefits of both traditional capacitors and rechargeable batteries
Previous reports have evidenced similar morphologies for activated carbon cloth, carbon fibers, and carbon felt [23,33,34,35,36]; electrochemical exfoliation of carbon materials generally leads to a significant improvement in electrode properties, including surface area
We present a simple and cost-effective method for the activation of carbon felt as an alternative, low-cost, and active material for use in supercapacitor devices
Summary
The electrical double-layer capacitors are electrical energy storage devices that offer attractive features, such as fast storing/releasing of energy, long cycling life, and high reversibility as they combine the benefits of both traditional capacitors and rechargeable batteries. They are commonly called supercapacitors [1,2]. Supercapacitors have emerged as preferable energy storage devices due to the specific properties, namely high power density, faster charge–discharge rates, and stable life cycle [3]. A crucial component of supercapacitor devices is the electrode material, which determines key performance parameters such as power, energy density, and stability [4,5,6].
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