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Rechargeable zinc-air batteries (ZABs) hold great promise for energy storage and conversion due to their high theoretical energy density, cost-effectiveness, and inherent safety. However, progress is constrained by sluggish oxygen electrocatalysis and instability at the air cathode. To address such issues, we resort to a directly integrated pseudo-3D composite electrocatalyst based on carbon cloth, on which Fe/Fe3C- and N- co-doped carbon nanotubes are directly induced and then used to further intercalate NiFe hydroxide clusters, FexNC@NiFe(OH)(x). This hierarchical electrocatalyst shows enhanced oxygen electrocatalysis (Delta E is 636 mV), rendering high efficiency and durability of ZABs. Such improvement can be attributed to the rationally integrated pseudo-3D structure with high conductivity, high density of active sites, interconnected porosity, and well-bonded components for accelerating electron transfer and ion diffusion while ensuring structural integrity. Moreover, the hierarchical structure increases the electrochemical surface area with superior surface hydrophilicity. As a result, the composite electrocatalyst shows great potential as a binder-free air electrode, as demonstrated in a rechargeable ZAB of a high power density of 85.1 mW cm(-2) and a long period of operation beyond 2000 cycles (350 h) without notable degradation, outperforming noble metal electrodes.

N/S-co-coped carbon nanoparticles (mean size ∼ 80–90 nm) have been synthesized by a simple strategy based on the preparation of polypyrrole nanospheres by a room temperature oxidative polymerization process followed by their S doping using elemental sulfur. The developed materials combine a highly disordered microstructure with a high level of N- and S-doping and short solid-state diffusion distances. These characteristics endow the materials with a large number of readily accessible adsorption/insertion sites for sodium storage, yielding thus high reversible capacities (of up to 726 mAh g−1 at 0.1 A g−1) that are well retained at high current rates (up to 188 mAh g−1 at 10 A g−1). The material with optimized Na storage performance was tested as the negative electrode in a sodium-ion capacitor, using as the positive electrode highly porous nanoparticles prepared by KHCO3 activation of the same polypyrrole nanospheres (SBET ∼ 2970 m2 g−1). The sodium-ion capacitor with an optimized positive-to-negative electrode mass ratio of 2 delivers as much as 69 Wh kg−1 at a high-power density of 25 kW kg−1, and can be successfully charged and discharged for 10000 cycles experiencing a capacity loss of only 0.0024% per cycle at 2 A g−1.

Copyright © 2019 American Chemical Society. Seeking economical, high-performance catalysts from natural waste to substitute traditional noble metal catalysts has been an emerging strategy in recent decades for energy catalysis and conversion devices. In this work, sustainable biomass kelp-derived self-nitrogen doped porous biomass carbon (PBC) with tunable pore structure and large specific surface areas was skillfully developed. The effect of calcination temperature on the pore structure and morphology of PBC was investigated to further optimize its performance. Honeycomb-like PBC exhibited high specific surface areas (805.2 m 2 g -1 ) and remarkable catalytically active nitrogen sites (higher to 1.51 wt %) with quantitative analysis. It largely enhanced its electrochemical performance such that the PBC-800 material showed excellent oxygen reduction reaction activity, and the electron transfer path of this process was fully explained by simulated density functional theory calculations. Interestingly, it possessed a high adsorption capacity for gaseous toluene (model fitted value of 332.23 mg g -1 ). On the basis of the above excellent properties, this kelp-based PBC might serve as a potentially bifunctional material for energy conversion and environmental purification.

A novel self-supporting carbon thin film flexible supercapacitor electrode with high volumetric and areal capacitance was developed. The increase in capacitance performance is achieved by introducing channels across the carbon thin film using ion-track technology. In the first step of the electrode synthesis, latent tracks are inscribed in the starting polyimide (Kapton) foil by irradiation with 253 MeV Kr ions. Next, macropores in the form of cylindrical channels are formed by selective chemical etching with NaOCl along the ion tracks, creating ion-track polymer. With subsequent carbonization and activation of the ion-track polymer, activated ion-track carbon is produced. A range of samples are obtained by varying the chemical etching time of the irradiated polymer. In addition to channel formation the chemical etching time influences the composition of surface functional groups. The best results are obtained by chemical etching for 40 min, the thickness of the sample is 21 A mu m with channel density 2.4 x 10(6) cm(-2) and average channel diameter 430 nm. Beside cylindrical macro channels this material is mainly microporous with 0.62 nm pore diameter and shows the highest areal (494 mF/cm(2)), volumetric (224 F/cm(3)) and gravimetric (178 F/g) capacitance. As a consequence of channel formation, the rate capability of the supercapacitor was also increased.

A novel self-supporting carbon thin film flexible supercapacitor electrode with high volumetric and areal capacitance was developed. The increase in capacitance performance is achieved by introducing channels across the carbon thin film using ion-track technology. In the first step of the electrode synthesis, latent tracks are inscribed in the starting polyimide (Kapton) foil by irradiation with 253 MeV Kr ions. Next, macropores in the form of cylindrical channels are formed by selective chemical etching with NaOCl along the ion tracks, creating ion-track polymer. With subsequent carbonization and activation of the ion-track polymer, activated ion-track carbon is produced. A range of samples are obtained by varying the chemical etching time of the irradiated polymer. In addition to channel formation the chemical etching time influences the composition of surface functional groups. The best results are obtained by chemical etching for 40 min, the thickness of the sample is 21 A mu m with channel density 2.4 x 10(6) cm(-2) and average channel diameter 430 nm. Beside cylindrical macro channels this material is mainly microporous with 0.62 nm pore diameter and shows the highest areal (494 mF/cm(2)), volumetric (224 F/cm(3)) and gravimetric (178 F/g) capacitance. As a consequence of channel formation, the rate capability of the supercapacitor was also increased.

Carbon based-supercapacitors are widely used in numerous applications but the knowledge of the specific role of carbon features in their performance is still insufficient. The main aim of this work is to warn readers that the current interpretation of the device operation, mostly based on powdered carbon properties, may be misleading in certain cases and should be complemented with the physicochemical characterization of the corresponding electrodes. Ordered mesoporous carbons highly enriched in surface functionalities were prepared by carbonization of 3-aminobenzoic acid into SBA-15 template. These carbons achieved a specific capacitance as high as 220 F/g in 2 M H2SO4 aqueous electrolyte. The pseudocapacitance contribution ranged between 35 and 70% of the overall capacitance. It was shown that the structural and textural changes underwent by these advanced carbons during their processing in form of electrodes prevented the full exploitation of their outstanding properties for high-power applications. This makes a difference regarding conventional, disordered activated carbons, which virtually preserve their structure during electrode preparation.

The present review is concerned with the results of long-lasting research on synthesis and properties of advanced carbon materials performed at the Vinca Institute of Nuclear Sciences: a) dependence of the structure and properties of medium- and high-temperature pyrolytic carbon (PC) on the conditions of synthesis; b) formation of solid solutions of B, Si and P in PC and effect of the presence of foreign elements on the structure and properties of PC; c) processes taking place during carbonization of phenolic resins and their effect on the properties of glass-like carbon prepared d) processes taking place during carbonization and activation of cellulose textile materials and their influence on the properties of activated textile; e) stabilization of polyacrylonitrile fibres by air oxidation and by SO2 treatment: effect of the synthesis conditions on the carbon fibres properties; f) rules governing chemical vapour infiltration of carbon in porous substrates and properties of the resulting composites; g) preparation of carbon/carbon composites by impregnation of carbon fibres with coal tar pitch and/or resin and their resulting properties. Application of the results of these investigations to develop and scale-up preparation technologies for the group of advanced materials has been outlined.

The present review is concerned with the results of long-lasting research on synthesis and properties of advanced carbon materials performed at the Vinca Institute of Nuclear Sciences: a) dependence of the structure and properties of medium- and high-temperature pyrolytic carbon (PC) on the conditions of synthesis; b) formation of solid solutions of B, Si and P in PC and effect of the presence of foreign elements on the structure and properties of PC; c) processes taking place during carbonization of phenolic resins and their effect on the properties of glass-like carbon prepared d) processes taking place during carbonization and activation of cellulose textile materials and their influence on the properties of activated textile; e) stabilization of polyacrylonitrile fibres by air oxidation and by SO2 treatment: effect of the synthesis conditions on the carbon fibres properties; f) rules governing chemical vapour infiltration of carbon in porous substrates and properties of the resulting composites; g) preparation of carbon/carbon composites by impregnation of carbon fibres with coal tar pitch and/or resin and their resulting properties. Application of the results of these investigations to develop and scale-up preparation technologies for the group of advanced materials has been outlined.