Holey TiC MXene-Derived Anode Enables Boosted Kinetics in Lithium-Ion Capacitors.

Lithium-ion capacitors (LICs) attract enormous attention because of the urgent demands for high power and energy density devices. However, the intrinsic imbalance between anodes and cathodes with different charge-storage mechanisms blocks the further improvement in energy and power density. MXenes, novel two-dimensional materials with metallic conductivity, accordion-like structure, and regulable interlayer spacing, are widely employed in electrochemical energy storage devices.

A nanostructured porous carbon/MoO composite with efficient catalysis in polysulfide conversion for lithium-sulfur batteries.

Lithium-sulfur batteries are considered as the next generation of energy storage systems because of their high theoretical specific capacity and energy density. Unfortunately, the sluggish reaction kinetics, weak adsorption toward to lithium polysulfides, and slow lithium ion diffusion impede the smooth electrochemical process, resulting in the lithium-sulfur batteries with the unsatisfactory cycling stability and rate performance. Since it is recognized that polar metal oxides and doped nitrogen in carbon materials have chemical interaction with lithium polysulfides, a nanostructured nitrogen-doped porous carbon/MoO composite is synthesized through a simple hydrothermal method by using graphene oxide nanoribbon and phosphomolybdic acid hydrate as precursors.

Investigating the Electrocatalysis of a TiC/Carbon Hybrid in Polysulfide Conversion of Lithium-Sulfur Batteries.

Despite the fact that lithium-sulfur batteries are regarded as promising next-generation rechargeable battery systems owning to high theoretical specific capacity (1675 mA h g) and energy density (2600 W h kg), several issues such as poor electrical conductivity, sluggish redox kinetics, and severe "shuttle effect" in electrodes still hinder their practical application. MXenes, novel two-dimensional materials with high conductivity, regulable interlayer spacing, and abundant functional groups, are widely applied in energy storage and conversion fields. In this work, a TiC/carbon hybrid with expanded interlayer spacing is synthesized by one-step heat treatment in molten potassium hydroxide.

Tuning Both Surface Chemistry and Porous Properties of Polymer-Derived Porous Carbons for High-Performance Gas Adsorption.

In this study, we have prepared novel pyrrole-formaldehyde polymers through polymerizing pyrrole and formaldehyde in the mixture solvent of water and ethanol by using hydrochloric acid as a catalyst. The as-synthesized polymers possess a nitrogen content of 6.7 atom % and are composed of spherical particles with the diameter of approximately 1-3 μm.

Nanostructured porous carbons derived from nitrogen-doped graphene nanoribbon aerogels for lithium-sulfur batteries.

A nanostructured porous carbon (NPC) is prepared by using a facile physical activation method, with nitrogen-doped graphene nanoribbon aerogel and carbon dioxide as a precursor and an activating agent, respectively. The morphology, porosity parameters, and chemical properties of the as-prepared NPC have been revealed by using various characterization methods, including scanning electron microscopy, nitrogen sorption analysis, and X-ray photoelectron spectroscopy (XPS). The NPC with a moderate nitrogen content (5.

Effect of Porosity Parameters and Surface Chemistry on Carbon Dioxide Adsorption in Sulfur-Doped Porous Carbons.

In this work, a series of highly porous sulfur-doped carbons are prepared through physical activation methods by using polythiophene as a precursor. The morphology, structure, and physicochemical properties are revealed by a variety of characterization methods, such as scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and nitrogen sorption measurement. Their porosity parameters and chemical compositions can be well-tuned by changing the activating agents (steam and carbon dioxide) and reaction temperature.

Metal-Organic Framework-Derived Metal Oxide Embedded in Nitrogen-Doped Graphene Network for High-Performance Lithium-Ion Batteries.

Metal-organic frameworks (MOFs) are hybrid inorganic-organic materials that can be used as effective precursors to prepare various functional nanomaterials for energy-related applications. Nevertheless, most MOF-derived metal oxides exhibit low electrical conductivity and mechanical strain. These characteristics limit their electrochemical performance and hamper their practical application.

Nitrogen-doped graphene aerogel as both a sulfur host and an effective interlayer for high-performance lithium-sulfur batteries.

Lithium-sulfur batteries have attracted great concern because of the high theoretical capacity of sulfur (1675 mA h g). However, the poor electrical conductivity and volumetric expansion of sulfur along with the dissolution of lithium polysulfides largely limit their practical application. In this study, nitrogen-doped graphene aerogel (NGA) with high nitrogen content and porosity is used as a host for the impregnation of sulfur.

Synthesis of Core-Shell Structured Porous Nitrogen-Doped Carbon@Silica Material via a Sol-Gel Method.

Core-shell structured nitrogen-doped porous carbon@silica material with uniform structure and morphology was synthesized via a sol-gel method. During this process, a commercial triblock copolymer and the in situ formed pyrrole-formaldehyde polymer acted as cotemplates, while tetraethyl orthosilicate acted as silica precursor. The synergetic effect of the triblock copolymer and the pyrrole-formaldehyde polymer enables the formation of the core-shell structure.

Preparation and characterization of a composite hydrogel with graphene oxide as an acid catalyst.

In this study, a facile method for synthesizing a novel graphene oxide/pyrrole-formaldehyde (GOP-1) composite hydrogel was developed via in situ polymerization of pyrrole and formaldehyde in the presence of graphene oxide sheets without any additional catalyst. During the polymerization, graphene oxide can act as a two-dimensional template to regulate the aggregation state of polymer and as an acid catalyst to accelerate the reaction rate of pyrrole and formaldehyde. The morphology and microstructure were investigated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, respectively.

Nitrogen-doped graphene aerogels as efficient supercapacitor electrodes and gas adsorbents.

Nitrogen-doped graphene has been demonstrated to be an excellent multifunctional material due to its intriguing features such as outstanding electrocatalytic activity, high electrical conductivity, and good chemical stability as well as wettability. However, synthesizing the nitrogen-doped graphene with a high nitrogen content and large specific surface area is still a challenge. In this study, we prepared a nitrogen-doped graphene aerogel (NGA) with high porosity by means of a simple hydrothermal reaction, in which graphene oxide and ammonia are adopted as carbon and nitrogen source, respectively.

Preparation of three-dimensional graphene oxide-polyethylenimine porous materials as dye and gas adsorbents.

We report a facile method for the fabrication of three-dimensional (3D) porous materials via the interaction between graphene oxide (GO) sheets and polyethylenimine (PEI) with high amine density at room temperature under atmospheric pressure without stirring. The structural and physical properties of GO-PEI porous materials (GEPMs) are investigated by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and nitrogen adsorption-desorption measurement and their chemical properties are analyzed by X-ray photoelectron spectroscopy, infrared spectroscopy, and Raman spectroscopy. GEPMs possess low density and hierarchical morphology with large specific surface area, and big pore volume.