Enhanced capacitance of nitrogen-doped hierarchically porous carbide-derived carbon in matched ionic liquids

Abstract

Supercapacitors combine efficient electrical energy storage and performance stability based on fast electrosorption of electrolyte ions at charged interfaces. They are a central element of existing and emerging energy concepts. A better understanding of capacitance enhancement options is essential to exploit the full potential of supercapacitors. Here, we report a novel hierarchically structured N-doped carbon material and a significant capacitance enhancement for a specific ionic liquid. Our studies indicate that matching of the electrode material and the ionic liquid specifically leads to a constant normalized resistance of the electrode material (voltage window up to AE1 V vs. carbon) and a significant enhancement of the specific capacitance. Such effects are not seen for standard organic electrolytes, non-matched ionic liquids, or non-N-doped carbons. A higher N-doping of the electrode material improves the symmetric full cell capacitance of the match and considerably increases its long-term stability at +3 V cell voltage. This novel observance of enhanced specific capacitance for N-doped carbons with matched ionic liquid may enable a new platform for developing supercapacitors with enhanced energy storage capacity.

Single-catalyst high-weight% hydrogen storage in an N-heterocycle synthesized from lignin hydrogenolysis products and ammonia

“…The polymer based synthesis protocol for SiCN, operating by crosslinking polysilazanes and subsequent pyrolysis, allows the introduction of porosity in various ways. For instance, metal-mediated nanoporosity34 and meso-structuring via sacrificial polyolefin components have been reported35363738.…”

Influence of Nitrogen‐Doping for Carbide‐Derived Carbons on the Supercapacitor Performance in an Organic Electrolyte and an Ionic Liquid

“…In the present study, we used a similar approach but varied the organic group to introduce nitrogen via silane to the ceramic material. Nitrogen in the carbide can still be found in the CDC material after chlorine gas treatment, as we know from previous work . We produced CDCs also with another silane to obtain porous carbon materials without nitrogen with a similar pore size distribution (average pore size of 1.6–1.9 nm and 94–99 % of the pore volume relates to pores smaller than 5 nm).…”

“…Along with this line of research, Ewert et al. reported that nitrogen‐doping of CDC leads to an enhanced specific capacitance for certain ionic liquids, such as EMIM‐BF 4 , while there was no enhancement for organic electrolytes based on acetonitrile as the solvent . Also, other groups investigated nitrogen‐doped carbon materials made from different precursors and reported high specific energy of up to 64 Wh/kg (measured at a cell voltage of 3.2 V) ,,,.…”

Ionic Liquids as Environmentally Benign Electrolytes for High‐Performance Supercapacitors

“…Ionic conductivities were compared to chitosan/adipic acid and chitosan/acetic acid binary electrolytes. Ewert et al have investigated matching compatibility of various porous N‐doped hierarchical carbon materials with different ionic liquids. They have shown the importance to adapt the IL with the electrode material, more particularly in terms of capacitance and long‐term stability; [EMIm][BF 4 ] and [EMIm][Tf 2 N] were more particularly investigated.…”