Chunming Yang

A Novel and Facile One-Pot Solvothermal Synthesis of PEDOT–PSS/Ni–Mn–Co–O Hybrid as an Advanced Supercapacitor Electrode Material

In this work, a novel and facile one-pot method has been developed for the synthesis of a hybrid consisting of Ni-Mn-Co ternary oxide and poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT-PSS/NMCO) with a hierarchical three-dimensional net structure via a solvothermal-coprecipitation coupled with oxidative polymerization route. Apart from the achievement of polymerization, coprecipitation, and solvothermal in one pot, the hydroxyl (OH(-)) ions generated from the oxidative polymerization of organic monomer by neutral KMnO4 solution were skillfully employed as precipitants for metal ions. As compared with the PEDOT-PSS/Ni-Mn binary oxide, PEDOT-PSS/Co-Mn binary oxide, and PEDOT-PSS/MnO2, PEDOT-PSS1.5/NMCO exhibits overwhelmingly superior supercapacitive performance, more specifically, a high specific capacitance of 1234.5 F g(-1) at a current density of 1 A g(-1), a good capacitance retention of 83.7% at a high current density of 5 A g(-1) after 1000 cycles, an energy density of 51.9 W h kg(-1) at a power density of 275 W kg(-1), and an energy density of 21.4 W h kg(-1) at an extremely elevated power density of 5500 W kg(-1). Noticeably, the energy density and power density of PEDOT-PSS/NMCO are by far higher than those of the existing analogues recently reported. The exceptional performance of PEDOT-PSS/NMCO benefits from its unique mesoporous architecture, which could provide a larger reaction surface area, faster ion and electron transfer ability, and good structural stability. The desirable integrated performance enables the multicomponent composite to be a promising electrode material for energy storage applications.

One-step pyrolysis synthesis of octahedral Fe3O4/C nanocomposites as superior anodes for sodium-ion batteries

Fe3O4/C nano-octahedra with a diameter of 300–500 nm have been successfully synthesized by a simple pyrolysis method. The Fe3O4/C displayed superior reversible capacity, rate capability and cycling performance as an anode for sodium-ion batteries. At a current density of 100 mA g−1, a large capacity of 380 mA h g−1 was still achieved after 60 cycles.

Facile synthesis of MnO 2 -embedded flower-like hierarchical porous carbon microspheres as an enhanced electrocatalyst for sensitive detection of caffeic acid

Tailored designs/fabrications of hierarchical porous advanced electrode materials are of great importance for developing high-performance electrochemical sensors. Herein, we demonstrate a simple and low-cost in situ chemical approach for the facile synthesis of MnO2-embedded hierarchical porous carbon microspheres (MnO2/CM). By the characterizations of scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction and energy dispersive spectroscopy, we evidenced that the synthesized product were flower-like carbon microspheres (CM) assembled by the bent flakes with thickness of about several nanometers and MnO2 nanorods were highly dispersed and successfully decorated on the CM layers, resulting in a rough surface and three-dimensional microstructure. The greatest benefit from the combined porous CM with MnO2 nanorods is that the MnO2/CM modified electrode has the synergetic catalysis effect on the electro-oxidation of caffeic acid, leading to the remarkable increase in the electron transfer rate and significant decrease in the over-potential for the caffeic acid oxidation in contrast to the bare electrode and CM modified electrode. This implies that the prepared MnO2/CM can be employed as an enhanced electrocatalyst for the sensitive detection of caffeic acid. Under the optimum conditions, the anodic peak current of caffeic acid is linear with its concentration in the range of 0.01-15.00xa0μmolxa0L-1, and a detection limit of 2.7xa0nmolxa0L-1 is achieved based on S/Nxa0=xa03. The developed sensor shows good selectivity, sensitivity, reproducibility, and also excellent recovery in the detections of real samples, revealing the promising practicality of the sensor for the caffeic acid detection.

N-doped carbon coated anatase TiO2 nanoparticles as superior Na-ion battery anodes

N-doped carbon coated TiO2 nanoparticles (TiO2@NC) were synthesized through a simple two-step route, in which dopamine was simultaneously utilized as both nitrogen and carbon sources. With TiO2@NC applied in the Na-ion battery (SIB) anodes, the continuous and uniform N-doped carbon layer can not only enhance the electrical conductivity of TiO2 and facilitate the surface pseudocapacitive process, but also serve as a buffer layer to accommodate the volume expansion during the sodiation-desodiation processes. The as-prepared TiO2@NC exhibits excellent electrochemical performance when utilized as the SIB anodes, which delivers a remarkably high reversible capacity of 250.2u202fmAhu202fg-1 at a rate of 0.25C (84u202fmAu202fg-1) after 200 cycles and still retains 122.1u202fmAhu202fg-1 at 10C (3.35u202fAu202fg-1) even after 3000 cycles accompanied with a 95.3% retention of the maximum capacity, outperforming most of the reported TiO2/C-based composites as SIB anodes. To our best knowledge, the preparation of TiO2@NC with dopamine as both nitrogen and carbon sources and its application in the SIB anodes are reported for the first time.