Phosphorus-doped ordered mesoporous carbons (POMCs) with different lengths were synthesized using a metal-free nanocasting method of SBA-15 mesoporous silica with different sizes as template and triphenylphosphine and phenol as phosphorus and carbon sources, respectively. The resultant POMC with a small amount of P doping is demonstrated as a metal-free electrode with excellent electrocatalytic activity for oxygen reduction reaction (ORR), coupled with much enhanced stability and alcohol tolerance compared to those of platinum via four-electron pathway in alkaline medium. Interestingly, the POMC with short channel length is found to have superior electrochemical performances compared to those with longer sizes.

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Nitrogen-doped turbostratic carbon nanoparticles (NPs) are prepared using fast single-step flame synthesis by directly burning acetonitrile in air atmosphere and investigated as an anode material for lithium-ion batteries. The as-prepared N-doped carbon NPs show excellent Li-ion stoarage properties with initial discharge capacity of 596 mA h g(-1), which is 17% more than that shown by the corresponding undoped carbon NPs synthesized by identical process with acetone as carbon precursor and also much higher than that of commercial graphite anode. Further analysis shows that the charge-discharge process of N-doped carbon is highly stable and reversible not only at high current density but also over 100 cycles, retaining 71% of initial discharge capacity. Electrochemical impedance spectroscopy also shows that N-doped carbon has better conductivity for charge and ions than that of undoped carbon. The high specific capacity and very stable cyclic performance are attributed to large number of turbostratic defects and N and associated increased O content in the flame-synthesized N-doped carbon. To the best of our knowledge, this is the first report which demonstrates single-step, direct flame synthesis of N-doped turbostratic carbon NPs and their application as a potential anode material with high capacity and superior battery performance. The method is extremely simple, low cost, energy efficient, very effective, and can be easily scaled up for large scale production.

Heteroatom and porosity both have different, but definite effect on the electrochemical capacitance of carbon materials. These effects are studied in details by cubic ordered mesoporous carbons (OMCs) co-doped with N and P. 3-dimentional (3D) mesoporous silica, KIT-6 with bicontinuous cubic Ia3d symmetry is utilized as a hard template to synthesize the cubic OMC. Interestingly, although the porosity parameters e.g. surface area and pore volume do not change much with N doping, a significant increase of these values is observed upon P doping. Moreover, the P content does not affect the N doping characteristics on co-doping of both N and P. When tested as supercapacitor electrode, the N-OMC despite much lower porosity parameters, exhibits similar specific capacitance compared with the P-OMC. High specific capacitance in N-OMC arises mainly from the pseudocapacitive effect of doped N species, whereas high porosity parameters are the main reason for the specific capacitance shown by P-OMC. The synergistic contribution of both effects enables the NP co-doped OMC to show highest specific capacitance of 210 F g -1 at 1.0 A g -1 . Moreover, excellent retention of specific capacitance with more than 90 % of initial capacitance is observed for NP-OMC at high current density of 10 A g -1 and also for 3000 charge-discharge cycles. This is mainly because of high-surface area hierarchical porous structures with uniform and ordered mesopores in the cubic OMC, which facilitate the unrestricted movement of electrolyte ions to access the active surfaces, as well as excellent synergistic effect of co-doping of N and P. This is also supported by electrochemical impedance spectroscopic analysis, which shows negligible mass transfer resistance and internal cell resistance. Overall, the synthesized cubic OMC materials are found to be highly promising as electrode for supercapacitor and other energyrelated applications.small size of these micropores (pore size < 2 nm) hinders the Cubic ordered mesoporous carbon co-doped with N and P shows high specific capacitance of 210 F g -1 at 1.0 A g -1 and excellent retention of specific capacitance with more than 90 % of initial capacitance at high current density of 10 A g -1 and also for 3000 charge-discharge cycles.

Agarose has been functionalized (acetylated/carbanilated) in an ionic liquid (IL) medium of 1-butyl-3-methylimidazolium acetate at ambient conditions. The acetylated agarose showed a highly hydrophobic nature, whereas the carbanilated agarose could be dissolved in water as well as in the IL medium. Thermoreversible ionogels were obtained by cooling the IL sols of carbanilated agarose at room temperature. The ionogel prepared from a protic-aprotic mixed-IL system (1-butyl-3-methylimidazolium chloride and N-(2-hydroxyethyl)ammonium formate) demonstrated a superior self-healing property, as confirmed from rheological measurements. The superior self-healing property of such an ionogel has been attributed to the unique inter-intra hydrogen-bonding network of functional groups inserted in the agarose. The ionogel was tested as a flexible solid electrolyte for an activated-carbon-based supercapacitor cell. The measured specific capacitance was found to be comparable with that of a liquid electrolyte system at room temperature and was maintained for up to 1000 charge-discharge cycles. Such novel functionalized-biopolymer self-healing ionogels with flexibility and good conductivity are desirable for energy-storage devices and electronic skins with superior lifespans and robustness.

We report the template-free pyrolysis of easily available natural seaweed, Undaria pinnatifida, as a single precursor, which results in "seaweed carbon" (SCup). Interestingly, thus-obtained SCup not only contains heteroatoms such as nitrogen and sulfur in its framework, but it also possesses a well-developed porous structure with high surface area. The heteroatoms in SCup originate from the nitrogen- and sulfur-containing ingredients in seaweed, whereas the porosity is created by removal of salts inherently present in the seaweed. These essential and fundamental properties make seaweed a prime choice as a precursor for heteroatom-containing highly porous carbon as a metal-free efficient electrocatalyst. As-synthesized SCup showed excellent electrocatalytic activity in the oxygen reduction reaction (ORR) in alkaline medium, which can be addressed in terms of the presence of the nitrogen and sulfur heteroatoms, the well-developed porosity, and the electrical conductivity in the carbon framework. The pyrolysis temperature was a key controlling parameter that determined the trade-off between heteroatom doping, surface properties, and electrical conductivity. In particular, SCup prepared at 1000 °C showed the best ORR performance. Additionally, SCup exhibited enhanced durability and methanol tolerance relative to the state of the art commercial Pt catalyst, which demonstrates that SCup is a promising alternative to costly Pt-based catalysts for the ORR.

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