Atomic Layer‐by‐Layer Co₃O₄/Graphene Composite for High Performance Lithium‐Ion Batteries

Abstract

An “atomic layer‐by‐layer” structure of Co3O4/graphene is developed as an anode material for lithium‐ion batteries. Due to the atomic thickness of both the Co3O4 nanosheets and graphene, the composite exhibits an ultrahigh specific capacity of 1134.4 mAh g−1 and an ultralong life up to 2000 cycles at 2.25 C, far beyond the performances of previously reported Co3O4/C composites.

General Synthesis of Transition Metal Oxide Ultrafine Nanoparticles Embedded in Hierarchically Porous Carbon Nanofibers as Advanced Electrodes for Lithium Storage

“…[12,52] The minor capacity fluctuation during the long-cycling test could be attributed to the unstability of the SEI film, the electrolyte degradation, the reaction of oxygen-containing functional groups on the carbon with lithium ions, and/or the small temperature fluctuation of the environment. [53] To further understand the outstanding electrochemical performance of ZnO UNPs@HPCNFs, TEM analysis (Figure 5f) was conducted to examine the morphological changes in the electrode after 500 charge/discharge cycles at 3 A g -1 . The TEM image obviously confirms that the porous structure of the carbon nanofibers is still well preserved after cycling for the ZnO UNPs@HPCNFs, which demonstrates that the tailored nanostructure of the TMOs UNPs@HPCNFs could effectively restrain the pulverization and aggregation of TMO nanograins during continuous lithiation and delithiation processes, thus ensuring high cycling stability.…”

Two‐Dimensional Metal Oxide Nanomaterials for Next‐Generation Rechargeable Batteries

“…by rationally employing lamellar reverse micelles (Figure 1). [98][99][100][101][102] Later, Xiao et al developed another strategy to synthesize 2D metal oxide nanosheets from solution by using the surfaces of water-soluble salt crystals as growth substrates or templates. In the synthesis, inverse lamellar micelles of Pluronic P123 polymer with a cosurfactant were used to confine the growth of the metal oxide along the thickness dimension and resulted in an atomic-level thickness of the obtained nanosheets.…”

Strategies for designing metal oxide nanostructures

“…Free-standing ultrathin 2D nanostructures are highly desirable for obtaining superior catalytic, photovoltaic, and electrochemical performances, due to their large surface-tovolume ratios and confined thickness on the atomic scale [152][153][154][155][156][157][158][159][160][161][162]. Strictly speaking, materials with few-layered atomic planes and 2D scalability should be called "2D crystals", which can also be called as "ultrathin nanosheets" due to their appearance [163].…”

“…Strictly speaking, materials with few-layered atomic planes and 2D scalability should be called "2D crystals", which can also be called as "ultrathin nanosheets" due to their appearance [163]. For example, the 2D carbon network-graphene-features extremely high carrier mobility, mechanical flexibility, optical transparency, and chemical stability, which provides a great opportunity for developing new electronic materials, novel sensors and metrology facilities, and superior energy conversion and storage devices [152][153][154][155][156]. Compared to the widely studied graphene and dichalcogenides, the ultrathin 2D transition metal oxide nanosheets have been relatively rarely studied, owing to the difficulties in the preparation of high quality 2D metal oxide nanomaterials.…”

“…At present, there are mainly three approaches to the fabrication of 2D metal oxide nanosheets, namely, liquid/chemical exfoliation of layered host materials, CVD growth, and wet-chemical self-assembly, as in the schematic illustration shown in Figs 4a-d [152][153][154][155][156][157][158][159][160][161][162][163]. Both the former two approaches start from bulk layered host materials to obtain low-dimensional nanomaterials; we usually call them forms of "top-down" synthesis.…”