Preparation of Porous Activated Carbons for High Performance Supercapacitors from Taixi Anthracite by Multi-Stage Activation.

Coal-based porous materials for supercapacitors were successfully prepared using Taixi anthracite (TXA) by multi-stage activation. The characterization and electrochemical tests of activated carbons (ACs) prepared in different stages demonstrated that the AC from the third-stage activation (ACIII) shows good porous structures and excellent electrochemical performances. ACIII exhibited a fine specific capacitance of 199 F g-1 at a current density of 1 A g-1 in the three-electrode system, with 6 mol L-1 KOH as the electrolyte. The specific capacitance of ACIII remained 190 F g-1 even despite increasing the current density to 5 A g-1, indicating a good rate of electrochemical performance. Moreover, its specific capacitance remained at 98.1% of the initial value after 5000 galvanostatic charge-discharge (GCD) cycle tests at a current density of 1 A g-1, suggesting that the ACIII has excellent cycle performance as electrode materials for supercapacitors. This study provides a promising approach for fabricating high performance electrode materials from high-rank coals, which could facilitate efficient and clean utilization of high-rank coals.

Analysis of soluble components in coals and interpretations for the complex mass spectra.

RATIONALE: The deduction of useful information from the mass spectra of a complex mixture like coals remains difficult, which limits the clean and efficient utilization of coals. It is necessary to explore the data interpretation methods for mass spectra and visualize the analytical data of coals for industrial utilization such as feedstock selection. METHODS: Coal sample and methanol were mixed and heated to 310 °C and kept at that temperature for 2 h. The solvent was under supercritical state at 310 °C and the solubility for the solid mixture increased. Soluble products from thermal dissolution of two Chinese coals were analyzed by high-performance liquid chromatography/atmospheric pressure chemical ionization orbitrap mass spectrometry. RESULTS: The iso-abundance plot for molecules in coals was upgraded to display the distributions of isomers which are indicated as concentric circles or triangles with the same carbon number and value of double-bond equivalent. The concentration ratio was introduced from economics to describe the content inequality of organic species within the same class of coal molecules. CONCLUSIONS: Interpretation methods for mass spectra visualize and simplify the understanding of complex components in coals for industrial utilization. Coals with a high concentration ratio for a specific class should take priority as a feedstock for chemicals and receive more attention. Copyright © 2016 John Wiley & Sons, Ltd.