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The limited Na‐storage capacity of graphite anodes for sodium‐ion batteries (∼110 mAh g−1) is significantly enhanced by the incorporation of nanosized Sn (17 wt%). The composite (SntGraphite), prepared by simple annealing of graphite with SnCl2, shows a specific capacity of 223 mAh g−1 (at 50 mA g−1) combined with excellent cycle life (i. e. 96 % of capacity retention after 2,200 cycles at 1 A g−1) and initial Coulomb efficiency (90 %). The combined storage of sodium in graphite (by solvent co‐intercalation) and Sn (by alloy formation) is followed by in situ X‐ray diffraction and in situ electrochemical dilatometry (ECD). While the additional tin almost doubles the electrode capacity, its contribution to the electrode expansion (∼3 %) is surprisingly small. The use of SntGraphite as anode for sodium‐ion hybrid capacitors with activated carbon as cathode provides a maximum energy and power density of ∼93 Wh kg−1 and 7.8 kW kg−1, with a capacity retention of ∼80 % after 8,000 cycles. [ABSTRACT FROM AUTHOR]

This work reports the facile synthesis of a Sn–P composite combined with nitrogen doped hard carbon (NHC) obtained by ball‐milling and its use as electrode material for sodium ion batteries (SIBs). The "Sn4P3"/NHC electrode (with nominal composition "Sn4P3":NHC = 75:25 wt%) when coupled with a diglyme‐based electrolyte rather than the most commonly employed carbonate‐based systems, exhibits a reversible capacity of 550 mAh gelectrode−1 at 50 mA g−1 and 440 mAh gelectrode−1 over 500 cycles (83% capacity retention). Morphology and solid electrolyte interphase formation of cycled "Sn4P3"/NHC electrodes is studied via electron microscopy and X‐ray photoelectron spectroscopy. The expansion of the electrode upon sodiation (300 mAh gelectrode−1) is only about 12–14% as determined by in situ electrochemical dilatometry, giving a reasonable explanation for the excellent cycle life despite the conversion‐type storage mechanism. In situ X‐ray diffraction shows that the discharge product is Na15Sn4. The formation of mostly amorphous Na3P is derived from the overall (electro)chemical reactions. Upon charge the formation of Sn is observed while amorphous P is derived, which are reversibly alloying with Na in the subsequent cycles. However, the formation of Sn4P3 can be certainly excluded. [ABSTRACT FROM AUTHOR]

Here, a simple and efficient preparation of NiCoO2 nanoparticle modified nanoporous bismuth vanadate (BiVO4) thin film and its application in photoelectrocatalytic (PEC) oxygen evolution reaction (OER) is demonstrated. The role of NiCoO2 in the composite electrode (BiVO4/NiCoO2) is twofold: OER cocatalyst and band structure modifier. It improves surface reaction kinetics for PEC OER and enhances charge separation efficiency simultaneously, which is believed to be a determining factor for the unprecedentedly high PEC OER performance of this BiVO4/NiCoO2 nanocomposite. The photocurrent density of 3.6 mA cm−2 at 1.23 V versus RHE in 0.1 m potassium phosphate buffered (pH = 7) electrolyte by BiVO4/NiCoO2 is three times that of BiVO4 and significantly higher than most literature values. The BiVO4/NiCoO2 nanocomposite shows/possess a high charge separation efficiency (ηsurface) of ≈72% as compared to only 23% for pure nanoporous BiVO4 at 1.23 V versus RHE, which demonstrates convincing role of NiCoO2 in the composite electrode. Both the excellent photocurrent density and great operational stability of this BiVO4/NiCoO2 nanocomposite makes it a promising photocatalytic material for practical applications. [ABSTRACT FROM AUTHOR]

In article number 1700540, Peng Wang and co‐workers report that bismuth vanadate (BiVO4), when assisted by nickel cobalt oxides (NiCoO2), shows vastly improved photo(electro)catalysis (PEC) oxygen evolution reaction (OER) performance. The role of NiCoO2 is two folds: OER cocatalyst and band structure adjustment. The dual‐role on single‐component NiCoO2 improves surface reaction kinetics for PEC OER and enhances charge separation on the surface BiVO4 simultaneously, which is the determining factor for the unprecedented performance. [ABSTRACT FROM AUTHOR]

The facile synthesis of a porous carbon material that is doped with iron-coordinated nitrogen active sites (FeNC-70) is demonstrated by following an inexpensive synthetic pathway with a zeolitic imidazolate framework (ZIF-70) as a template. To emphasize the possibility of tuning the porosity and surface area of the resulting carbon materials based on the structure of the parent ZIF, two other ZIFs, that is, ZIF-68 and ZIF-69, are also synthesized. The resulting active carbon material that is derived from ZIF-70, that is, FeNC-70, exhibits the highest BET surface area of 262 m(2) g(-1) compared to the active carbon materials that are derived from ZIF-68 and ZIF-69. The HR-TEM images of FeNC-70 show that the carbon particles have a bimodal structure that is composed of a spherical macroscopic pore (about 200 nm) and a mesoporous shell. X-ray photoelectron spectroscopy (XPS) reveals the presence of Fe-N-C moieties, which are the primary active sites for the oxygen-reduction reaction (ORR). Quantitative estimation by using EDAX analysis reveals a nitrogen content of 14.5 wt.%, along with trace amounts of iron (0.1 wt.%), in the active FeNC-70 catalyst. This active porous carbon material, which is enriched with Fe-N-C moieties, reduces the oxygen molecule with an onset potential at 0.80 V versus NHE through a pathway that involves 3.3-3.8 e(-) under acidic conditions, which is much closer to the favored 4 e(-) pathway for the ORR. The onset potential of FeNC-70 is significantly higher than those of its counterparts (FeNC-68 and FeNC-69) and of other reported systems. The FeNC-based systems also exhibit much-higher tolerance towards MeOH oxidation and electrochemical stability during an accelerated durability test (ADT). Electrochemical analysis and structural characterizations predict that the active sites for the ORR are most likely to be the in situ generated N-FeN(2+2)/C moieties, which are distributed along the carbon framework., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)