The right kind of interior for multifunctional electrode architectures: carbon nanofoam papers with aperiodic submicrometre pore networks interconnected in 3D

Materials and fabrication of electrode scaffolds for deposition of MnO2 and their true performance in supercapacitors

“…Generally, scaffolds with large thicknesses, such as CNTs arrays on Ta foil (35 mm) [45], CNTs arrays on carbon cloth (50 mm) [75], 3D graphene networks (ca. 200 mm) [66] and carbon nanofoam paper (230 mm) [46] could afford high MnO 2 mass loading while maintain a reasonable good specific capacitance performance and rate capability. Besides, combining MnO 2 with conducting polymer, like PPy [78,79], to form coreeshell hybrid structures could also achieve high specific capacitances at relatively high MnO 2 mass loadings.…”

“…This is because the incorporation of nanoscale MnO 2 within the nanoporous electrode scaffolds will not change the volume of the scaffolds. For instance, incorporating of MnO 2 within the free-standing nanoporous gold sheets (100 nm in thickness) led to an ultrahigh volumetric capacitance of 1160 F cm À3 at 50 mV s À1 [47]; incorporation of homogeneous nanoscale MnO 2 into nanofoam paper with thickness (230 mm) comparable to that of commercial carbon electrodes (100e200 mm) also led to a good volumetric capacitance of 280 F cm À3 [46], more than twice of that value of commercial activated carbon electrodes (112 F cm…”

“…In some occasions, the electrode scaffolds can act as active materials for energy storage themselves, such as carbon nanofoam paper [46] and Co 3 O 4 nanowire arrays [63]. Materials for construction of electrode scaffolds for loading of MnO 2 must be discriminated by their: 1) Chemical stability in aqueous electrolytes 2) Electrochemical stability during the charging-discharging process 3) Low density 4) High conductivity 5) Low costs 6) Good processability to form porous structures Metal and carbon materials are widely used for fabrication of nanostructured current collectors.…”

Extending Electrochemical Quartz Crystal Microbalance Techniques to Macroscale Electrodes: Insights on Pseudocapacitance Mechanisms in MnOx-Coated Carbon Nanofoams

“…We examined two nanofoam pore structures with primary pore sizes in the small mesopore range, 5-20 nm (nanofoams designated as "50/500") or broadly distributed from 10-200 nm ("40/1500" nanofoams). 26 Additionally, qualitative results indicate that there is very little change in motional resistance of the electrode during potential cycling (not shown). Thus, for the purposes of our discussion, we assume that the solvent within the pores of the nanofoams is rigidly coupled.…”

“…26 Nanoscale MnOx coatings were deposited by soaking carbon nanofoams in an aqueous solution of 0.1 M NaMnO 4 in 0.1 M Na 2 SO 4 under vacuum for 20 h. 11,27,28,31 The MnOx-coated carbon nanofoams were removed from the aqueous MnO 4 -solution, rinsed well with water (18 M cm), and dried at 50…”