Template-Directing Coupled with Chemical Activation Methodology-Derived Hexagon-like Porous Carbon Electrode with Outstanding Compatibility to Electrolytes and Low-Temperature Performance.

The conversion of asphalt into hexagon-like porous carbon (HPC) with a micro-mesoporous structure is realized by the coupling of template-directing and chemical activation methodologies. The specific surface area of HPC can reach up to 1356 m2 g-1 even at such a low-proportioned dosage of activator (0.5-fold) and is also larger than those of template-directed carbon and activation-derived carbon, as it benefited from the coupling merits of template-directing and chemical activation. Excellent capacitive-energy-storage behavior with respect to rate capability, capacitance retention, and durability are delivered by HPC//HPC symmetric supercapacitors assembled with aqueous and organic electrolytes. This great compatibility for different kinds of electrolytes and electrode properties is owed to the robust hexagon-like microarchitecture feature associated with hierarchical pore structure, which not only hinders the stacking between each other but also provides a buffer function for the volume variation and sufficient active sites for the storage of electrolyte ions. The drastic temperature variation has almost no influence on the diffusion and transfer rate of electrolyte ions, further evidencing the advanced feature of the hierarchical pore structure. Additionally, HPC//Li4Ti5O12 LIC assembled with the Li-based electrolyte also presents a superior Ragone performance. The coexistence of micro- and mesopores for the HPC makes it an attractive electrode material for various capacitive-energy-storage devices. This work provides a promising way to realize the plasticity of pore channels and mass production of high capacitive storage ability of electrode material via the combination of template-directing and chemical activation strategies.

High Capacitive Energy Storage of Nest-Like Porous Graphene Microspheres Electrode with High Mass Loading.

Nest-like porous graphene microspheres (NPGMs) are grown by using a chemical vapor deposition (CVD) method in a fluidized bed reactor from methane and basic magnesium carbonate microspheres (synthesized by a stirring-induced crystallization approach) as carbon source and template, respectively. The CVD-derived NPGMs have a few-layer structure and high electrical conductivity, as well as a three-dimensional individual macroarchitecture accompanied with well-developed pore channels and great structural integrity. As the electrode for a symmetric supercapacitor, the effect of different mass loadings for NPGMs-based electrodes on the capacitive energy-storage performance is investigated. Superior electrochemical properties with respect to gravimetric, areal, and total capacitances, rate capability, and durability are shown by the NPGMs-based symmetric supercapacitors, even at mass loadings up to 10 mg cm-2 . Moreover, the electrochemical behavior of the NPGMs-based electrode is much superior to those of two-dimensional lamella-like graphene and commercial activated carbon.

Phosphorus and nitrogen dual-doped few-layered porous graphene: a high-performance anode material for lithium-ion batteries.

Few-layered graphene networks composed of phosphorus and nitrogen dual-doped porous graphene (PNG) are synthesized via a MgO-templated chemical vapor deposition (CVD) using (NH4)3PO4 as N and P source. P and N atoms have been substitutionally doped in graphene networks since the doping takes place at the same time with the graphene growth in the CVD process. Raman spectra show that the amount of defects or disorders increases after P and N atoms are incorporated into graphene frameworks. The doping levels of P and N measured by X-ray photoelectron spectroscopy are 0.6 and 2.6 at %, respectively. As anodes for Li ion batteries (LIBs), the PNG electrode exhibits high reversible capacity (2250 mA h g(-1) at the current density of 50 mA g(-1)), excellent rate capability (750 mA h g(-1) at 1000 mA g(-1)), and satisfactory cycling stability (no capacity decay after 1500 cycles), showing much enhanced electrode performance as compared to the undoped few-layered porous graphene. Our results show that the PNG is a promising candidate for anode materials in high-rate LIBs.

High capacity gas storage in corrugated porous graphene with a specific surface area-lossless tightly stacking manner.

We report for the first time an experimental investigation of gas storage in porous graphene with nanomeshes. High capacity methane storage (236 v(STP)/v) and a high selectivity to carbon dioxide adsorption were obtained in the nanomesh graphene with a high specific surface area (SSA) and a SSA-lossless tightly stacking manner.