Dou, S. (2016). Nitrogen-doped graphene ribbon assembled coresheath MnO@Graphene scrolls as hierarchically ordered 3D porous electrodes for fast and durable lithium storage. Advanced Functional Materials, 26 (43), 7754-7765. Nitrogen-doped graphene ribbon assembled core-sheath MnO@Graphene scrolls as hierarchically ordered 3D porous electrodes for fast and durable lithium storage AbstractGraphene scroll is an emerging 1D tubular form of graphitic carbon that has potential applications in electrochemical energy storage. However, it still remains a challenge to composite graphene scrolls with other nanomaterials for building advanced electrode configuration with fast and durable lithium storage properties. Here, a transition-metal-oxide-based hierarchically ordered 3D porous electrode is designed based on assembling 1D core-sheath MnO@N-doped graphene scrolls with 2D N-doped graphene ribbons. In the resulting architecture, porous MnO nanowires confined in tubular graphene scrolls are mechanically isolated but electronically wellconnected, while the interwoven graphene ribbons offer continuous conductive paths for electron transfer in all directions. Moreover, the elastic graphene scrolls together with enough internal voids are able to accommodate the volume expansion of the enclosed MnO. Because of these merits, the asbuilt electrode manifests ultrahigh rate capability (349 mAh g−1 at 8.0 A g−1; 205 mAh g−1 at 15.0 A g−1) and robust cycling stability (812 mAh g−1 remaining after 1000 cycles at 2.0 A g−1) and is the most efficient MnO-based anode ever reported for lithium-ion batteries. This unique multidimensional and hierarchically ordered structure design is believed to hold great potential in generalizable synthesis of graphene scrolls composited with oxide nanowires for mutifuctional energy storage.Keywords core-sheath, mno@graphene, nitrogen-doped, ordered, 3d, porous, electrodes, fast, durable, graphene, scrolls, hierarchically, lithium, storage, assembled, ribbon Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsZhang, Y., Chen, P., Gao, X., Wang, B., Liu, H., Wu, H., Liu, H. & Dou, S. (2016). Nitrogen-doped graphene ribbon assembled core-sheath MnO@Graphene scrolls as hierarchically ordered 3D porous electrodes for fast and durable lithium storage. Advanced Functional Materials, 26 (43), 7754-7765. AuthorsYun Zhang, Penghui Chen, Xu Gao, Bo Wang, Heng Liu, Haobin Wu, Hua-Kun Liu, and Shi Xue Dou This journal article is available at Research Online: http://ro.uow.edu.au/aiimpapers/2275 1 PUBLISHED TITLE -"Nitrogen-doped graphene ribbon assembled core-sheath MnO@Graphene scrolls as hierarchically ordered 3D porous electrodes for fast and durable lithium storage" Engineering 3D Hierarchical Anode Configuration Based on Nitrogen-Doped Graphene-Scrolled MnO Coaxial Nanocables for Superior Lithium StorageHao Wu, Penghui Chen, Yi Guo, Bo Wang, Wenjing Liu, Heng Liu, Yun Zhang, Shixue Dou, and Huakun Liu Keywords: hierarchical structure; graphene scrolls; nitrogen doping; MnO n...

No abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.201905842. Rechargeable Zn/MnO 2 batteries using mild aqueous electrolytes are attracting extensive attention due to their low cost, high safety, and environmental friendliness. However, the charge-storage mechanism involved remains a topic of controversy so far. Also, the practical energy density and cycling stability are still major issues for their applications. Herein, a free-standing α-MnO 2 cathode for aqueous zinc-ion batteries (ZIBs) is directly constructed with ultralong nanowires, leading to a rather high energy density of 384 mWh g −1 for the entire electrode. Greatly, the H + /Zn 2+ coinsertion mechanism of α-MnO 2 cathode for aqueous ZIBs is confirmed by a combined analysis of in situ X-ray diffractometry, ex situ transmission electron microscopy, and electrochemical methods. More interestingly, the Zn 2+ -insertion is found to be less reversible than H + -insertion in view of the dramatic capacity fading occurring in the Zn 2+ -insertion step, which is further evidenced by the discovery of an irreversible ZnMn 2 O 4 layer at the surface of α-MnO 2 . Hence, the H + -insertion process actually plays a crucial role in maintaining the cycling performance of the aqueous Zn/α-MnO 2 battery. This work is believed to provide an insight into the charge-storage mechanism of α-MnO 2 in aqueous systems and paves the way for designing aqueous ZIBs with high energy density and long-term cycling ability. www.advancedsciencenews.com

As a result of its high‐energy density, metal–selenides have demanded attention as a potential energy‐storage material. But they suffer from volume expansion, dissolved poly‐selenides and sluggish kinetics. Herein, utilizing' thermal selenization via the Kirkendall effect, microspheres of NiSe2 confined by carbon are successfully obtained from the self‐assembly of Ni‐precursor/PPy. The derived hierarchical hollow architecture increases the active defects for sodium storage, while the existing double N‐doped carbon layers significantly alleviate the volume swelling. As a result, it shows ultrafast rate capability, delivering a stable capacity of 374 mAh g−1, even after 3000 loops at 10.0 A g−1. These remarkable results may be ascribed to the NiOC bonds on the interface of NiSe2 and the carbon film, which leads to the faster transfer of ions, the effective trapping of poly‐selenide, and the highly reversible conversion reaction. The kinetic analysis of cyclic voltammetry (CV) demonstrates that the electrochemical process is mainly dominated by pseudocapacitive behaviors. Supported by the results of electrochemical impedance spectroscopy (EIS), it is confirmed that the solid–electrolyte interface films are reversibly formed/decomposed during cycling. Given this, this elaborate work might open up a potential avenue for the rational design of metal‐sulfur/selenide anodes for advanced battery systems.

No abstract