Carbon Coating and Zn 2+ Doping of Magnetite Nanorods for Enhanced Electrochemical Energy Storage

Zn Metal Atom Doping on the Surface Plane of One-Dimesional NiMoO4 Nanorods with Improved Redox Chemistry

The effect of zinc (Zn) doping and defect formation on the surface of nickel molybdate (NiMoO₄) structures with varying Zn content has been studied to produce one-dimensional electrodes and catalysts for electrochemical energy storage and ethanol oxidation, respectively. Zn-doped nickel molybdate (Ni_1-xZn_xMoO₄, where x = 0.1, 0.2, 0.4, and 0.6) nanorods were synthesized by a simple wet chemical route. The optimal amount of Zn is found to be around 0.25 above which the NiMoO₄ becomes unstable, resulting in poor electrochemical activity. This result agrees with our density functional theory calculations in which the thermodynamic stability reveals that Ni_1-xZn_xMoO₄ crystallized in the β-NiMoO₄ phase and is found to be stable for x≤0.25. Analytical techniques show direct evidence of the presence of Zn in the NiMoO₄ nanorods, which subtly alter the electrocatalytic activity. Compared with pristine NiMoO₄, Zn-doped NiMoO₄ with the optimized Zn content was tested as an electrode for an asymmetric supercapacitor and demonstrated an enhanced specific capacitance of 122 F g^-1 with a high specific energy density of 43 W h kg^-1 at a high power density of 384 W kg^-1. Our calculations suggest that the good conductivity from Zn doping is attributed to the formation of excess oxygen vacancies and dopants play an important role in enhancing the charge transfer between the surface and OH^- ions from the electrolyte. We report electrochemical testing, material characterization, and computational insights and demonstrate that the appropriate amount of Zn in NiMoO₄ can improve the storage capacity (∼15%) due to oxygen vacancy interactions.

Facile Synthesis of ZnO Nanoparticles on Nitrogen-Doped Carbon Nanotubes as High-Performance Anode Material for Lithium-Ion Batteries

ZnO/nitrogen-doped carbon nanotube (ZnO/NCNT) composite, prepared though a simple one-step sol-gel synthetic technique, has been explored for the first time as an anode material. The as-prepared ZnO/NCNT nanocomposite preserves a good dispersity and homogeneity of the ZnO nanoparticles (~6 nm) which deposited on the surface of NCNT. Transmission electron microscopy (TEM) reveals the formation of ZnO nanoparticles with an average size of 6 nm homogeneously deposited on the surface of NCNT. ZnO/NCNT composite, when evaluated as an anode for lithium-ion batteries (LIBs), exhibits remarkably enhanced cycling ability and rate capability compared with the ZnO/CNT counterpart. A relatively large reversible capacity of 1013 mAh·g⁻¹ is manifested at the second cycle and a capacity of 664 mAh·g⁻¹ is retained after 100 cycles. Furthermore, the ZnO/NCNT system displays a reversible capacity of 308 mAh·g⁻¹ even at a high current density of 1600 mA·g⁻¹. These electrochemical performance enhancements are ascribed to the reinforced accumulative effects of the well-dispersed ZnO nanoparticles and doping nitrogen atoms, which can not only suppress the volumetric expansion of ZnO nanoparticles during the cycling performance but also provide a highly conductive NCNT network for ZnO anode.

Fe3O4 nanoparticles encapsulated in multi-walled carbon nanotubes possess superior lithium storage capability

Fe₃O₄ nanoparticles are successfully introduced inside multi-walled carbon nanotubes (Fe₃O₄@MWNTs) by an innovative wet chemical injection method.

Fabricating three-dimensional mesoporous carbon network-coated LiFePO4/Fe nanospheres using thermal conversion of alginate-biomass

Three-dimensional mesoporous carbon network-coated LiFePO₄/Fe nanospheres with high-rate capability.

Effects of Fe2+ ion doping on LiMnPO4 nanomaterial for lithium ion batteries

Carbon-coating and Fe-doping of LiMnPO₄ resulted in superior cycling and rate performance as LIB cathode materials.

Facile synthesis of MgFe2O4/C composites as anode materials for lithium-ion batteries with excellent cycling and rate performance

A MgFe₂O₄/C material is synthesized via a facile method and the MgFe₂O₄/C electrode shows excellent cycling and rate capability.

Multifunctional Carbon Nanostructures for Advanced Energy Storage Applications

Carbon nanostructures-including graphene, fullerenes, etc.-have found applications in a number of areas synergistically with a number of other materials. These multifunctional carbon nanostructures have recently attracted tremendous interest for energy storage applications due to their large aspect ratios, specific surface areas, and electrical conductivity. This succinct review aims to report on the recent advances in energy storage applications involving these multifunctional carbon nanostructures. The advanced design and testing of multifunctional carbon nanostructures for energy storage applications-specifically, electrochemical capacitors, lithium ion batteries, and fuel cells-are emphasized with comprehensive examples.

Rechargeable Co3O4 porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Multi-walled carbon nanotube nanocomposites intertwined with porous Co₃O₄ nanoflakes serve as lithium-ion battery anode materials with enhanced performances.

Enhanced electrochemical performances of MoO2 nanoparticles composited with carbon nanotubes for lithium-ion battery anodes

Lab-made CNT nanocomposites decorated with MoO₂ nanoparticles (MoO₂/CNTs) demonstrated superior cycling and rate performances as LIB anode materials.

Carbon coated manganese monoxide octahedron negative-electrode for lithium-ion batteries with enhanced performance

Carbon coated MnO octahedra with narrow size distribution and good dispersity have been fabricated and applied as lithium ion battery anode materials.