Nitrogen doped superporous carbon prepared by a mild method. Enhancement of supercapacitor performance

Abstract

Nitrogen functionalization (ca. 4 at. % N XPS ) of a highly microporous activated carbon (S BET >3000m 2 /g) has been achieved by two different approaches at mild conditions: (i) oxidation and post-reaction with nitrogen reactants, and (ii) direct reaction of pristine carbon material with nitrogen reactants. Interestingly, the introduction of nitrogen functionalities allows full preservation of the microporosity when pathway (ii) is followed. The electrochemical performance of the carbon materials as electrodes for supercapacitors was evaluated by using symmetric and asymmetric configuration in 1M H 2 SO 4 . Both nitrogen-functionalized carbon materials showed larger stability and energy efficiency than the pristine carbon material when working at 1.4V. The non-oxidized and functionalized activated carbon evidences the best performance as electrode for supercapacitor, providing energy and power density of 14.5 Wh/kg and 61.2 kW/kg and keeping 83% of original capacitance after 5000 charge-discharge cycles.This improvement is related to the presence of surface nitrogen functionalities that provide a higher electrochemical stability, avoiding the formation of detrimental oxygen groups during the operation of the supercapacitor.

Ultraporous nitrogen-doped zeolite-templated carbon for high power density aqueous-based supercapacitors

“…In accordance to this finding, the maximum power obtained for N-ZTC based capacitor (calculated from the resistance measured from the ohmic drop of GCD cycles, which is in good agreement to that obtained from the EIS analyses) is four times larger than the value obtained for ZTC cell. This value outperforms those found in the literature for other carbon electrodes in supercapacitors [5,51,52], such as activated carbons (61.2 kW/kg in 1M H2SO4) [17], activated carbon nanofibers (20 kW/kg in 6M KOH) [53], hierarchical porous carbons (52.7 kW/kg in 1M H2SO4) [54], carbon nanotubes (43.3 kW/kg in 1M Et4NBF4/propylene carbonate) [55] and other templated carbons (28kW/kg in 1M H2SO4) [56]. This outstanding improvement of N-ZTC based capacitor is probably a consequence of its connected nanopore structure, which facilitates the accessibility of the electrolyte [4], and the large quantity of N-Q functionalities and pyrrole on the surface of this material, that are able to increase both wettability and electrical conductivity [18,20,44,45].…”

“…For shaping the electrodes, a sample sheet was cut into a circular shape with an area of 1. based on the total active weight of the carbon material in the cell (two electrodes). The energy density and power density were calculated as described elsewhere [17]. Table 1 summarizes the chemical properties of the samples.…”

“…The electrochemical performance of carbon materials can be tuned by the introduction of heteroatoms (such as O, N, P or B) [7][8][9][10][11][12][13][14][15][16]. Concretely, nitrogen functional groups have been found to modify the electrochemical stability, electrical conductivity, the wettability and pseudocapacitance of carbon materials [8,[17][18][19][20]. Nevertheless, the role of the different N functionalities still is not fully understood.…”

Nitrogen and Sulfur Doped Mesoporous Carbons, Prepared from Templating Silica, as Interesting Material for Supercapacitors

“…1 A g À 1 1523 1 M 336 N at 5.6% [54] 24 TDICN 532.5 n.a. 1 A g À 1 3114.74 1 M 171 N at < 1% [55] 25 N-CNFs/RGO/BC 318 8 10 mV s À 1 614 1 M 518 N at 3.6% [56] 26 KUA-N 59 6.6 1 A g À 1 3450 1 M 17 N at 4.1% [57] 27 NPC-GA-2 608 5 0.1 A g À 1 473 1 M 1285 N wt 7.3% [58] 28 NPC-1 368.7 2.5 1 A g À 1 736 1 M 501 N at 11.3% [59] 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57…”

Effect of physical activation/surface functional groups on wettability and electrochemical performance of carbon/activated carbon aerogels based electrode materials for electrochemical capacitors

“…Electrochemical impedance spectroscopy was used to analyse the resistive behaviour and to approximate the capacitive performance of the electrode material. Electrochemical capacitors behave like a resistor at very high frequencies (near the origin of the curve close to the Y-axis) however with the decrease in frequencies a sharp increase in the imaginary part of the resistance takes place and the curve becomes almost vertical due to the capacitive behaviour [45]. This indicates that by controlling the pore size and increasing the specific surface area through activation the capacitive behaviour of the electroactive material and final performance of the cell can be improved.…”