Synthesis and characterization of uniform nanoparticles of γ-Mo_2N for supercapacitors

Uniform nanoparticles of molybdenum nitride were synthesized by temperature-programmed reaction(TPR) using MoO3 and ammonia as reactants. This material was characterized by X-ray diffractometry(XRD), transmission electron microscopy(TEM), scanning electron microcopy(SEM) and cyclic voltammetry(CV). Results show that the material consists of a pure phase of γ-Mo2N nanoparticles with average diameter of about 16 nm. The material presents a specific capacitance of 172 F/g in 1 mol/L H2SO4 electrolyte at a scan rate of 1 mV/s and the potential window is broadened to 1.1 V (-0.6 to 0.5 V). At the 6 000th cycle, the material remains 94.9% and 94.7% of the initial capacitance in 1 mol/L H2SO4 and KCl solution, respectively. A possible mechanism comprising surface control and diffusion control is proposed to explain the effect of scan rates on specific capacitance.

In-situ design and construction of lithium-ion battery electrodes on metal substrates with enhanced performances：A brief review

For the ever-growing demand of advanced lithium-ion batteries, it is highly desirable to grow self-supported micro-/nanostructured arrays on metal substrates as electrodes directly. The in-situ growth of electrode materials on the conducting substrates greatly simplifies the electrode fabrication process without using any binders or conductive additives. Moreover, the well-ordered arrays closely connected to the current collectors can provide direct electron transport pathways and enhanced accommodation of strains arisen from lithium ion lithiation/delithiation. This article summarizes our recent work on design and construction of lithium-ion battery electrodes on metal substrates. An aqueous solution-based process and a microemulsion-mediated process have been respectively presented to control the kinetic and thermodynamic processes for the micro-/nanostructured array growth on metal substrates, with particular attention to CuO nanorod arrays and microcog arrays successfully prepared on Cu foil substrates. They can be directly used as binder-free electrodes to build advanced lithium-ion batteries with high energy, high safety and high stability.

Biotemplated synthesis of three-dimensional porous MnO/C-N nanocomposites from renewable rapeseed pollen： An anode material for lithium-ion batteries

Lithium-ion batteries （LIBs） are currently recognized as one of the most popular power sources available. To construct advanced LIBs exhibiting long-term endurance, great attention has been paid to enhancing their poor cycle stabilities. As the performance of LIBs is dependent on the electrode materials employed, the most promising approach to improve their life span is the design of novel electrode materials. We herein describe the rational design of a three-dimensional （3D） porous MnO/C-N nanoarchitecture as an anode material for long cycle life LIBs based on their preparation from inexpensive, renewable, and abundant rapeseed pollen （R-pollen） via a facile immersion-annealing route. Remarkably, the as-prepared MnO/C-N with its optimized 3D nanostructure exhibited a high specific capacity （756.5 mAh·g^-1 at a rate of 100 mA·g^-1）, long life span （specific discharge capacity of 513.0 mAh·g^-1, -95.16% of the initial reversible capacity, after 400 cycles at 300 mA·g^-1）, and good rate capability. This material therefore represents a promising alternative candidate for the high-performance anode of next-generation LIBs.