General Synthesis of Transition-Metal Oxide Hollow Nanospheres/Nitrogen-Doped Graphene Hybrids by Metal-Ammine Complex Chemistry for High-Performance Lithium-Ion Batteries

N-doped 3D porous carbon materials derived from hierarchical porous IRMOF-3 using a citric acid modulator: fabrication and application in lithium ion batteries as anode materials

N-doped three-dimensional carbon nanostructured materials were obtained by calcinating hierarchical porous IRMOF-3 materials, and were fabricated in the presence of citric acid as a modulator via the conventional synthetic protocol, at 900 °C in an Ar atmosphere. The resultant carbon materials were used as anode materials for lithium ion batteries, and exhibited excellent lithium storage capacity and cycling stability and maintained a capacity of about 555 mA h g^-1 at the current density of 0.2 A g^-1 after 100 cycles.

Fully water-blown polyisocyanurate-polyurethane foams with improved mechanical properties prepared from aqueous solution of gelling/ blowing and trimerization catalysts

Fully water-blown polyisocyanurate-polyurethane (PIR-PUR) foams with improved mechanical properties have been prepared using aqueous solutions of metal-ammonia complex, Cu(Am) or Zn(Am), as gelling/blowing catalysts and potassium octoate (KOct) solution in diethylene glycol as a trimerization catalyst. Two catalyst mixtures, Cu(Am)+KOct and Zn(Am)+KOct, were obtained as homogeneous aqueous solutions. In comparison to commercial catalyst system, DMCHA+KOct (DMCHA = N,N-dimethylcyclohexylamine), Cu(Am) and Zn(Am) could be miscible with KOct solution and water easier than DMCHA. This miscibility improvement led Cu(Am)+KOct and Zn(Am)+KOct to show faster catalytic reactivity in PIR-PUR foam reactions than DMCHA+KOct. All obtained PIR-PUR foams showed self-extinguishing properties and achieved HF1 materials. However, PIR-PUR foams prepared from Cu(Am)+KOct and Zn(Am)+KOct at NCO:OH ratio of 2:1 had suitable density for industrial applications and showed higher compressive strength than that prepared from DMCHA+KOct. These foams have high potential to apply as insulations for constructions, core laminates in wall panel or storage tanks.

Nb2O5 Nanoparticles Anchored on an N-Doped Graphene Hybrid Anode for a Sodium-Ion Capacitor with High Energy Density

Sodium-ion capacitors (SICs) have gained great interest for mid- to large-scale energy storage applications because of their high energy and high power densities as well as long cycle life and low cost. Herein, a T-Nb₂O₅ nanoparticles/N-doped graphene hybrid anode (T-Nb₂O₅/NG) was prepared by solvothermal treating a mixed ethanol solution of graphene oxide (GO), urea, and NbCl₅ at 180 °C for 12 h, followed by calcining at 700 °C for 2 h, in which T-Nb₂O₅ nanoparticles with average size of 17 nm were uniformly anchored on the surface of the nitrogen-doped reduced GO because their growth and aggregation were hindered, and also, the electronic conductivity and the active sites of T-Nb₂O₅/NG were improved by doping nitrogen. The T-Nb₂O₅/NG anode showed superior rate capability (68 mA h g^-1 even at 2 A g^-1) and good cycling life (106 mA h g^-1 at 0.2 A g^-1 for 200 cycles and 83 mA h g^-1 at 1 A g^-1 for 1000 cycles) and also showed high-rate pseudocapacitive behavior from kinetics analysis. A novel SIC system had been constructed by using the T-Nb₂O₅/NG as anode and commercially activated carbon as the cathode; it delivered an energy density of 40.5 W h kg^-1 at a power density of 100 W kg^-1 and a long-term cycling stability (capacity retention of 63% after 5000 consecutive cycles at a current density of 1 A g^-1) and showed a promising application for highly efficient energy storage systems.

N-Doped graphene with anchored ZnFe2O4 nanostructures as an anode for lithium ion batteries with enhanced reversible capacity and cyclic performance

The challenges in developing more efficient lithium ion (Li-ion) batteries as a power source have been the subject of tremendous research due to the increase in demand for high-power unplugged electronics.