Electrochemical investigation of sodium reactivity with nanostructured Co3O4 for sodium-ion batteries

The electrochemical behaviour of Co₃O₄ with sodium is reported here.

Graphene anchored with ZrO2 nanoparticles as anodes of lithium ion batteries with enhanced electrochemical performance

Graphene decorated with ZrO₂ nanoparticles shows excellent cycle and rate performance as anode material of lithium-ion batteries.

Assembly of MnO2 nanowires@reduced graphene oxide hybrid with an interconnected structure for a high performance lithium ion battery

MnO₂ nanowires@rGO hybrid delivers a high reversible capacity of 1079 mA h g⁻¹ over 200 cycles at a current density of 500 mA g⁻¹, and excellent rate capability.

Co3O4/carbon aerogel hybrids as anode materials for lithium-ion batteries with enhanced electrochemical properties

A facile hydrothermal and sol-gel polymerization route was developed for large-scale fabrication of well-designed Co3O4 nanoparticles anchored carbon aerogel (CA) architecture hybrids as anode materials for lithium-ion batteries with improved electrochemical properties. The three-dimensional (3D) mesoporous Co3O4/CA hierarchical hybrids display an improved lithium storage performance and cycling stability, because of the intimate integration and strong synergistic effects between the Co3O4 nanoparticles and CA matrices. Such an interconnected Co3O4/CA hierarchical hybrid can effectively utilize the good conductivity, large surface area, 3D interconnected mesoporous structure, mechanical flexibility, chemical stability, and the short length of Li-ion transport of the CA matrix. The incorporation of Co3O4 nanoparticles into the interconnected CA matrix effectively reduces the number of active sites of Co3O4/CA hybrids, thus greatly increasing the reversible specific capacity and the initial Coulombic efficiency of the hybrids. The Co3O4/CA hybrid material displays the best lithium storage performance and good cycling stability as the Co3O4 loading content is up to 25 wt %, retains a Coulombic efficiency of 99.5% and a specific discharge capacity of 779 mAh g(-1) after 50 cycles, 10.1 and 1.6 times larger than the specific discharge capacity of 73 mAh g(-1) and 478 mAh g(-1) for Co3O4 and CA samples, respectively. The hierarchical hybrid nanostructures with enhanced electrochemical activities using a CA matrix framework can find potential applications in the related conversion reaction electrodes.

Free-standing and binder-free lithium-ion electrodes based on robust layered assembly of graphene and Co3O4 nanosheets

Free-standing and binder-free Co3O4/graphene films were fabricated through vacuum filtration and thermal treatment processes, in which sheet-like Co3O4 and graphene were assembled into a robust lamellar hierarchical structure via electrostatic interactions. The morphological compatibility coupled with strong interfacial interactions between Co3O4 and graphene significantly promoted the interfacial electron and lithium ion transport. When used as a binder-less and free-standing electrode for lithium-ion batteries, the hybrid film delivered a high specific capacity (~1400 mA h g(-1) at 100 mA g(-1) based on the total electrode weight), enhanced rate capability and excellent cyclic stability (~1200 mA h g(-1) at 200 mA g(-1) after 100 cycles). This effective strategy will provide new insight into the design and synthesis of many other composite electrodes for high-performance lithium-ion batteries.

Template-free synthesis of amorphous double-shelled zinc-cobalt citrate hollow microspheres and their transformation to crystalline ZnCo2O4 microspheres

A novel and facile approach was developed for the fabrication of amorphous double-shelled zinc-cobalt citrate hollow microspheres and crystalline double-shelled ZnCo2O4 hollow microspheres. In this approach, amorphous double-shelled zinc-cobalt citrate hollow microspheres were prepared through a simple route and with an aging process at 70 °C. The combining inward and outward Ostwald ripening processes are adopted to account for the formation of these double-shelled architectures. The double-shelled ZnCo2O4 hollow microspheres can be prepared via the perfect morphology inheritance of the double-shelled zinc-cobalt citrate hollow microspheres, by calcination at 500 °C for 2 h. The resultant double-shelled ZnCo2O4 hollow microspheres manifest a large reversible capacity, superior cycling stability, and good rate capability.

Electric papers of graphene-coated Co₃O₄ fibers for high-performance lithium-ion batteries

A facile strategy to synthesize the novel composite paper of graphene nanosheets (GNS) coated Co(3)O(4) fibers is reported as an advanced anode material for high-performance lithium-ion batteries (LIBs). The GNS were able to deposit onto Co(3)O(4) fibers and form the coating via electrostatic interactions. The unique hybrid paper is evaluated as an anode electrode for LIBs, and it exhibits a very large reversible capacity (∼840 mA h g(-1) after 40 cycles), excellent cyclic stability and good rate capacity. The substantially excellent electrochemical performance of the graphene/Co(3)O(4) composite paper is the result from its unique features. Notably, the flexible structure of graphenic scaffold and the strong interaction between graphene and Co(3)O(4) fibers are beneficial for providing excellent electronic conductivity, short transportation length for lithium ions, and elastomeric space to accommodate volume varies upon Li(+) insertion/extraction.