Surface and electrochemical properties of amino-fluorinated activated carbon

This study introduces amino-fluorination, a novel chemical modification method for activated carbon (AC), and investigates the surface and electrochemical properties of the resulting AC. The procedure was modified by controlling the surface reaction with concentrated ammonium hydroxide and diluted hydrofluoric acid or diluted ammonium hydroxide and concentrated hydrofluoric acid. Amino-fluorination of AC with concentrated ammonium hydroxide and diluted hydrofluoric acid significantly increased the specific surface area, total pore volume, mesopore volume, and number of N- and F-containing surface functional groups and decreased the number of O-containing surface functional groups. These changes resulted in improving the specific capacity to 417 F/g at a scan rate of 10 mV s−1 from the specific capacity of raw AC-based EDLCs (241 F/g). On the other hand, amino-fluorination of AC with diluted ammonium hydroxide and concentrated hydrofluoric acid increased the specific surface area, total pore volume, mesopore volume, and number of N-, O-, and F-containing surface functional groups. These changes resulted in the highest specific capacitance for the prepared AC-based EDLCs (485 F/g), with a 101% increase compared to the raw-AC-based EDLCs. Therefore, the amino-fluorination of AC is a simple and efficient way to enhance the performance of AC-based EDLCs.

Graphical abstractThe novel chemical modification method of AC, amino-fluorination, increases the specific capacity of the modified AC-based EDLC more than twice of that of the untreated AC-based EDLC.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Amino-fluorination of ACs induces changes in textural properties of the resulting ACs. ► Amino-fluorination of ACs induces changes in surface chemical compositions of the resulting ACs. ► The above mentioned changes induced by amino-fluorination of ACs resulted in increased specific capacitances of the resulting AC-based EDLC electrodes.