Iron oxides are promising to be utilized in rechargeable alkaline battery with high capacity upon complete redox reaction (Fe 3+ Fe 0 ). However, their practical application has been hampered by the poor structural stability during cycling, presenting a challenge that is particularly huge when binder-free electrode is employed. This paper proposes a "carbon shellprotection" solution and reports on a ferroferric oxide-carbon (Fe 3 O 4 -C) binder-free nanorod array anode exhibiting much improved cyclic stability (from only hundreds of times to >5000 times), excellent rate performance, and a high capacity of ≈7776.36 C cm −3 (≈0.4278 C cm

Lithium ion battery (LIB) is potentially one of the most attractive energy storage devices. To meet the demands of future high-power and high-energy density requirements in both thin-film microbatteries and conventional batteries, it is challenging to explore novel nanostructured anode materials instead of conventional graphite. Compared to traditional electrodes based on nanostructure powder paste, directly grown ordered nanostructure array electrodes not only simplify the electrode processing, but also offer remarkable advantages such as fast electron transport/collection and ion diffusion, sufficient electrochemical reaction of individual nanostructures, enhanced material-electrolyte contact area and facile accommodation of the strains caused by lithium intercalation and de-intercalation. This article provides a brief overview of the present status in the area of LIB anodes based on one-dimensional nanostructure arrays growing directly on conductive inert metal substrates, with particular attention to metal oxides synthesized by an anodized alumina membrane (AAM)-free solution-based or hydrothermal methods. Both the scientific developments and the techniques and challenges are critically analyzed.

Layered double hydroxide (LDH) nano‐ and microstructures with controllable size and morphology have been fabricated on “bivalent metal” substrates such as zinc and copper by a one‐step, room‐temperature process, in which metal substrates act as both reactants and supports. By manipulating the concentration of NH3 · H2O, the thickness and lateral size of the LDH materials can be tuned from several tens of nanometers to several hundreds of nanometers and from several hundreds of nanometers to several micrometers, respectively. This method is general and may be readily extended to any other alkali‐resisted substrate coated with Zn and Cu. As an example, Zn‐covered stainless steel foil has been shown to be effective for the growth of a ZnAl LDH film. After calcinating the as‐grown LDH at high temperature (650 °C) in argon gas, a ZnO/ZnAl2O4 porous nanosheet film is obtained, which is then directly used for the first time as the anode material for Li‐ion batteries with the operating voltage window of 0.05–2.5 V (vs. Li). The result demonstrates that ZnO/ZnAl2O4 has higher discharge and charge capacities and considerably better cycling stability compared to pure ZnO (Li insertion/extraction rate: 200 or 500 mA g−1). The improved electrochemical performance can be ascribed to the buffering effect of the inactive matrix ZnAl2O4 by relieving the stress caused by the volume change during charge–discharge cycling. This work represents a successful example for the development of promising ZnO‐based anode materials for Li‐ion batteries.

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