Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

Abstract

Nitrogen incorporation into carbon increases metallic character and capacitance, however high concentrations are instead disruptive and decrease interfacial capacitance.

Reactive Plasma N-Doping of Amorphous Carbon Electrodes: Decoupling Disorder and Chemical Effects on Capacitive and Electrocatalytic Performance

“…A similar increase of the capacitance by a factor of 2 is observed at 10 Hz; notably, a comparison of values obtained at 0.1 vs. 10 Hz indicates dispersion in the capacitive response. This is generally observed in disordered/heterogeneous electrodes (Pajkossy, 1994;Kerner and Pajkossy, 2000), and had been previously reported also in the case of bulk-doped nitrogenated amorphous carbons (Hoque et al, 2019). The absence of a further increase in capacitance when increasing the exposure time from 10 to 20 min, suggests that additional amorphization negatively affects long-range properties and metallic character of the carbon material, in agreement with observed trends following ion bombardment of graphene (Van Tuan et al, 2012;Zhong et al, 2014) and after progressive bulk nitrogenation in amorphous carbons (Behan et al, 2017;Hoque et al, 2019).…”

“…Plasma treatment results in a change in capacitance values at 0.1 and 10 Hz, however the p-type character of the material is preserved, indicating that the introduction of N-sites via this surface treatment does not significantly change the semiconducting character. This is in stark contrast to the effect of bulk nitrogen incorporation which instead was shown by our group to result in a capacitive response with greater n-type character (Hoque et al, 2019) in amorphous carbons. The minimum of the interfacial capacitance at 0.1 Hz (see Supporting Information) was found to increase by ca.…”

Untangling Cooperative Effects of Pyridinic and Graphitic Nitrogen Sites at Metal‐Free N‐Doped Carbon Electrocatalysts for the Oxygen Reduction Reaction

“…flux of a total of 50 sccm. After deposition the resulting films were transported immediately to a tube furnace and annealed under N2 for 1 h. a-C NH3 700 and a-C NH3 900 were prepared by first depositing Nitrogen-free a-C films via DC magnetron sputtering using an Ar plasma [28,[52][53][54] and subsequently treating them with NH3 in a tube furnace according to the following program. First, the temperature of the furnace was ramped to 900 °C under a 200 mL min -1 N2 flow and held at this temperature for 1 h. For a-C NH3 900 electrodes, the gas composition was changed to 50:50 NH3 / N2 mixture with a total flow of 200 mL min -1 .…”

Template-free preparation of anthracite-based nitrogen-doped porous carbons for high-performance supercapacitors and efficient electrocatalysts for the oxygen reduction reaction

“…Considerable efforts have recently been made to prepare various porous carbon materials with high surface areas and well-developed porosities for improving the performance of electrochemical energy storage and conversion devices. [15][16][17][18][19][20] Porous carbons with hierarchical micro/mesopore structures have unique advantages to be promising energy materials. A large number of micropores with pore size of <2 nm are able to increase specic surface area and provide as many reaction sites as possible for capacitance formation and catalytic processes, whereas mesopores can serve as efficient transport pathways to improve ion transport kinetics.…”

“…[31][32][33] One of the major synthetic methods for N-doped carbons is post heat treatment of carbon sources under the atmosphere of a Ncontaining gas (usually NH 3 ). 16,18,24 In comparison, direct doping using N-containing solid-state precursors, such as melamine and urea, is another feasible way with high security and reliability. 17,34 Melamine is a nitrogen-enriched, inexpensive and abundant compound with an excellent doping effect.…”