C-Plasma of Hierarchical Graphene Survives SnS Bundles for Ultrastable and High Volumetric Na-Ion Storage.

Tin and its derivatives have provoked tremendous progress of high-capacity sodium-ion anode materials. However, achieving high areal and volumetric capability with maintained long-term stability in a single electrode remains challenging. Here, an elegant and versatile strategy is developed to significantly extend the lifespan and rate capability of tin sulfide nanobelt electrodes while maintaining high areal and volumetric capacities. In this strategy, in situ bundles of robust hierarchical graphene (hG) are grown uniformly on tin sulfide nanobelt networks through a rapid (5 min) carbon-plasma method with sustainable oil as the carbon source and the partially reduced Sn as the catalyst. The nucleation of graphene, CN (with size N ranging from 1 to 24), on the Sn(111) surface is systematically explored using density functional theory calculations. It is demonstrated that this chemical-bonded hG strategy is powerful in enhancing overall electrochemical performance.

Ultrathin MoSe2@N-doped carbon composite nanospheres for stable Na-ion storage.

Two-dimensional transition metal dichalcogenides are widely studied as anode materials for metal ion batteries. This application requires high electric conductivity which can be achieved by forming composites with conductive carbon. In this work, we demonstrate the creation of nanospheres composed of Mo-based thin nanosheets (MoS2, MoSe2 and Mo2C) uniform embedded within a N-doped carbon matrix. Using MoSe2/N-doped carbon nanospheres as an example, we investigate in detail the electrochemical property in Na ion storage and reveal the advantage over previously reported MoSe2 electrodes (higher capacity and improved capacity retention up to 500 cycles). Furthermore, we provide evidence by ex situ x-ray diffraction to the nominal irreversible conversion reaction during the first discharge.

Rapid Synthesis of Cobalt Nitride Nanowires: Highly Efficient and Low-Cost Catalysts for Oxygen Evolution.

Electrochemical splitting of water to produce hydrogen and oxygen is an important process for many energy storage and conversion devices. Developing efficient, durable, low-cost, and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is of great urgency. To achieve the rapid synthesis of transition-metal nitride nanostructures and improve their electrocatalytic performance, a new strategy has been developed to convert cobalt oxide precursors into cobalt nitride nanowires through N2 radio frequency plasma treatment. This method requires significantly shorter reaction times (about 1 min) at room temperature compared to conventional high-temperature NH3 annealing which requires a few hours. The plasma treatment significantly enhances the OER activity, as evidenced by a low overpotential of 290 mV to reach a current density of 10 mA cm(-2) , a small Tafel slope, and long-term durability in an alkaline electrolyte.