Solvent-Free Synthesis of N/S-Codoped Hierarchically Porous Carbon Materials from Protic Ionic Liquids for Temperature-Resistant, Flexible Supercapacitors

Abstract

A versatile precursor of protic ionic liquids ([Megl]­[HSO4]) was used to prepare N/S-codoped hierarchically porous carbon materials (N/S-HPC) by a double soft-template solvent-free self-assembly method. [Megl]­[HSO4] as carbon source, heteroatoms source and microporous forming agent, F127 as mesoporous soft-template and sodium dodecyl sulfate as macroporous soft-template have self-assembly in the curing process, and then are direct pyrolyzed to acquire N/S-HPC. The optimal sample shows large specific surface area of 1210 m2 g–1, high heteroatom doping (N: 5.31 at. %, S: 3.02 at. %, O: 5.56 at. %) and hierarchically porous structure with micropores (0.8–1.8 nm), mesopores (2.1–7.3 nm) and macropores (54–147 nm). The incorporation of N, S and O atoms into the carbon skeleton structure improves electrical conductivity and surface wettability, and provides additional pseudocapacitance. The results make N/S-HPC not only display high specific capacitance of 347 F g–1 at 0.5 A g–1 and still 174 F g–1 even at 20 A g–1 but also excellent cyclic stability of almost 100% capacitance retention for 5000 cycles in 6 M KOH electrolyte. Furthermore, the N/S-HPC still maintains excellent electrochemical property and stability under extreme temperatures (−20–+100 °C) and bending (0°–180°). Meanwhile, the as-assembled symmetric supercapacitor displays a superior energy density of 15.8 Wh kg–1 at the power density of 212.4 W kg–1, outstanding capacitive performance of 157 F g–1 at 0.5 A g–1 with a large electrochemical window of 1.7 V in 1 M Na2SO4 electrolyte.

One‐Pot Synthesis of Sulfur and Nitrogen Co‐Functionalized Graphene Material using Deep Eutectic Solvents for Supercapacitors

“…The DES is associatedw ith ac holine cation ands ulfur anion. [26,34,35] The DES showed peaks at d [26,35,36] TGA characterizations of the DESa nd ChCl were also performed ( Figure S5, Supporting Information); [26,37,38] here, we found around2 2% moisture loss at 100-200 8Ci nt he TGA data of the DES, indicating the hygroscopic natureo ft he DES. Alargercation will provide better nucleophilicity to associated anionsi ncomparison with as maller cation owing to the loose association between them.…”

“…The DES and ChClw erec haracterizedb y 1 HNMR spectroscopy( 400 MHz, D 2 O) to check the deshielding effecto ft he relative anion.I nt he case of ChCl we observed peaks at d = 3.95-3.91 (m, 2H), 3.41-3.38 (m, 2H), and 3.07 ppm (s, 9H) ( Figure S2, Supporting Information). [26,34,35] The DES showed peaks at d [26,35,36] TGA characterizations of the DESa nd ChCl were also performed ( Figure S5, Supporting Information); [26,37,38] here, we found around2 2% moisture loss at 100-200 8Ci nt he TGA data of the DES, indicating the hygroscopic natureo ft he DES. [38] This was also correlated with KF titration at room temperature.…”

“…[26] Liu et al designed and fabricated at ernary FeS@porous carbon nanowires/reducedg raphene oxide (rGO) hybrid film anode throughs caleup assembly and sulfuration methodologies. [26] Liu et al designed and fabricated at ernary FeS@porous carbon nanowires/reducedg raphene oxide (rGO) hybrid film anode throughs caleup assembly and sulfuration methodologies.…”

“…Sc o-doped hierarchically porous carbon materials through a double soft-template solvent-free self-assembly method. [26] Liu et al designed and fabricated at ernary FeS@porous carbon nanowires/reducedg raphene oxide (rGO) hybrid film anode throughs caleup assembly and sulfuration methodologies. [27] Li et al reported an efficient approach exploiting biomass as the precursorf or the preparation of 3D N/O-doped carbon frameworks with pyrolysis temperatures from 500 to 800 8Cb yu sing hydrothermala nd pyrolysis/activation methods.…”

Adapting a Kinetics-Enhanced Carbon Nanostructure to Li/Na Hybrid Water-in-Salt Electrolyte for High-Energy Aqueous Supercapacitors

“…Upon cycling, the Li 10 Na 3 OTf-loaded device reveals high electrochemical recoverability (98%, Figure S16a), desirable capacitive endurance (85.5% energy retention after 10 000 successive cycling at 10 A g –1 , Figure a), and Coulombic efficiency (98.4%, Figure a). Correspondingly, the energy supply reaches 39.2 Wh kg –1 @550 W kg –1 and maintains at 28.2 Wh kg –1 @22 kW kg –1 (Figures b and S16b,c), outperforming those of other reported aqueous devices. ,,,,,,− The appropriate compatibility of carbon nanostructure/electrolyte integrates their respective advantages (Figure c), providing the possibility for electronic applications with different rated voltages. More attractively, a single device successfully supports the timer (1.5 V) to work continuously over 6 h (Figure d).…”