CHEMPHYSCHEM CONTENTS
COVER PICTURE The picture shows a snapshot from a molecular dynamics simulation, presented on p. 2003 by W. Schmickler et al. for OH adsorbed on Pt(111) from an aqueous solution. The OH can be seen on the left with a red oxygen and a green hydrogen atom. Superimposed is a free energy surface for the reaction showing the adsorbed OH on the left, a chemisorbed OH in the center, and a solvated OH at the right.
NEWS Spotlights on our sister journals
1918 – 1921
REVIEWS The importance of the chemical history of the electrode surface before electrochemical cycling as well as the correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior of LiFePO4 and LiNi1/2Mn1/2O2 electrodes are investigated by magic-angle-spinning nuclear magnetic resonance, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. These techniques allow the study of interface aging and failure mechanisms.
N. Dupr,* M. Cuisinier, J.-F. Martin, D. Guyomard
Danger, high voltage! LiNi0.5Mn1.5O4 high-voltage spinel is a promising candidate for next-generation cathode materials, but its commercialization is hampered by electrolyte instability and concurrent parasitic reactions at electrode/ electrolyte interfaces (see figure). The known challenges in LiNi0.5Mn1.5O4/ graphite full-cell systems are reviewed. In addition, multiple strategies to overcome the issues and prolong the cycle life of full cells are introduced.
J.-H. Kim,* N. P. W. Pieczonka, L. Yang
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1922 – 1938 Interphase Evolution at Two Promising Electrode Materials for Li-Ion Batteries: LiFePO4 and LiNi1/2Mn1/2O2
1940 – 1954 Challenges and Approaches for HighVoltage Spinel Lithium-Ion Batteries
ChemPhysChem 2014, 15, 1907 – 1914
1907
CHEMPHYSCHEM CONTENTS S. Tan, Y. J. Ji, Z. R. Zhang, Y. Yang* 1956 – 1969 Recent Progress in Research on HighVoltage Electrolytes for Lithium-Ion Batteries
www.chemphyschem.org Safe and stable: Developing a stable and safe electrolyte that works at high voltages is a formidable challenge in present Li-ion-battery research. Recent progress in the development of several promising high-voltage electrolyte systems is summarized and reviewed.
MINIREVIEWS S. Ha , J.-K. Kim , A. Choi, Y. Kim,* K. T. Lee* 1971 – 1982 Sodium–Metal Halide and Sodium–Air Batteries
L. M. Peter,* K. G. Upul Wijayantha* 1983 – 1995 Photoelectrochemical Water Splitting at Semiconductor Electrodes: Fundamental Problems and New Perspectives
Power sauce: Sodium batteries such as Na–metal halide (see picture) and Na–air batteries are considered to be promising for use in electric vehicles owing to good safety and high energy density. This Minireview provides an overview of the fundamentals of and recent progress in the fields of Na– metal halide and Na–air batteries, with the aim of providing a better understanding of new electrochemical systems. Artificial photosynthesis—the generation of chemical fuels from water and sunlight—is one of the key scientific challenges for the 21st century. This review takes a closer look at recent progress in the field of light-driven water splitting at semiconductor electrodes and highlights some of the current bottlenecks that need to be addressed if dreams are to become reality.
COMMUNICATIONS R. A. Martnez-Rodrguez, F. J. Vidal-Iglesias, J. Solla-Gulln, C. R. Cabrera, J. M. Feliu* 1997 – 2001 Synthesis and Electrocatalytic Properties of H2SO4-Induced (100) Pt Nanoparticles Prepared in Water-in-Oil Microemulsion
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Shapewear for nanoparticles: Sulfuric acid is used as a surface modifier to synthesize (100) Pt nanoparticles (NPs) by using a water-in-oil microemulsion method. The electrocatalytic properties of the resulting cubic-like Pt NPs are evaluated towards ammonia and CO electro-oxidations.
ChemPhysChem 2014, 15, 1907 – 1914
1908
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
ARTICLES An adsorbed fraction of water: Adsorption of the hydroxyl ion has been studied by a formalism that combines DFT with molecular dynamics (see figure). The results suggest that OH can be adsorbed on PtACHTUNGRE(111) either as a metastable, physisorbed ion or as a chemisorbed radical. The energy of activation is of the order of 0.6 eV, so the adsorption is fast.
L. M. C. Pinto, P. Quaino, M. D. Arce, E. Santos, W. Schmickler*
Top of the PECs: N-doped reduced graphene oxide (nRGO) is systematically incorporated into the photoanode, cathode, and redox electrolyte of a photoelectrochemical cell and was shown to favorably influence the cell performance.
J. Selvaraj, S. Gupta, S. DelaCruz, V. Subramanian*
Inverted reactivity order: Ethanol oxidation on platinum single-crystal electrodes in alkaline solutions produces mainly acetate and the activity order is the opposite of that found in acid solutions. The formation of acetaldehyde deactivates the surface (see picture).
C. Bus-Rogero, E. Herrero,* J. M. Feliu
Methanol adsorption rate: At Pt electrodes, methanol is oxidized either to dissolved intermediates or—in parallel—to CO2 via adsorbed CO. The adsorption rate of methanol is dependent on the surface structure and increases with the step density. A further increase is observed upon step decoration by Ru.
E. Mostafa, A. A. Abd-El-Latif, H. Baltruschat*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2003 – 2009 Electrochemical Adsorption of OH on PtACHTUNGRE(111) in Alkaline Solutions: Combining DFT and Molecular Dynamics
2010 – 2018 Role of Reduced Graphene Oxide in the Critical Components of a CdSSensitized TiO2-Based Photoelectrochemical Cell
2019 – 2028 Ethanol Oxidation on Pt Single-Crystal Electrodes: Surface-Structure Effects in Alkaline Medium
2029 – 2043 Electrocatalytic Oxidation and Adsorption Rate of Methanol at Pt Stepped Single-Crystal Electrodes and Effect of Ru Step Decoration: A DEMS Study
1909
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
G. A. Attard,* A. Brew, J.-Y. Ye, D. Morgan, S.-G. Sun 2044 – 2051 Oxygen Reduction Reaction Activity on PtACHTUNGRE{111} Surface Alloys PtM overlayers (M = Fe, Co or Ni) supported on a PtACHTUNGRE{111} electrode are prepared via thermal annealing of aqueous droplets containing MZ + cations directly attached to the electrode. When a hydrogen ambient is used for thermal an-
N. Myung,* W. Lee, C. Lee, S. Jeong, K. Rajeshwar*
nealing, highly active oxygen reduction electrocatalysts are formed. A positive potential shift in PtM oxide formation is seen compared to PtACHTUNGRE{111}, which correlates with increased oxygen reduction reaction activity.
Bismuth vanadate and gold-modified bismuth vanadate are synthesized for the first time by a two-step anodic electrodeposition-galvanic replacement hybrid scheme. The metal-modified sample shows higher visible-light absorption, higher anodic photocurrent, and superior photocatalytic activity relative to the virgin sample.
2052 – 2057 Synthesis of Au-BiVO4 Nanocomposite through Anodic Electrodeposition Followed by Galvanic Replacement and Its Application to the Photocatalytic Decomposition of Methyl Orange
N. G. Hçrmann, A. Groß*
A polar exploration: An expression is derived that describes the effect of electron transfer between two exposed polar surfaces due to the internal electric field generated by the surfaces. This expression is applied to Li2FeSiO4, which is of interest as a possible electrode material for future Li-ion batteries.
2058 – 2069 Polar Surface Energies of IonoCovalent Materials: Implications of a Charge-Transfer Model Tested on Li2FeSiO4 Surfaces
J. Ming, W.-J. Kwak, J.-B. Park, C.-D. Shin, J. Lu, L. Curtiss, K. Amine,* Y.-K. Sun* 2070 – 2076 A Physical Pulverization Strategy for Preparing a Highly Active Composite of CoOx and Crushed Graphite for Lithium–Oxygen Batteries
Taking a beating: A new physical pulverization strategy has been developed to prepare a highly active composite of
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
CoOx/crushed graphite for the cathode in lithium–oxygen batteries.
ChemPhysChem 2014, 15, 1907 – 1914
1910
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
Experimental and computational techniques are applied to explore the reactivity of tri(ethylene glycol)-substituted trimethylsilane, a siloxane-based ether electrolyte, at a lithium-metal anode. The study indicates that both protection of the lithium metal and prevention of oxygen crossover to the anode are essential for minimizing electrolyte and anode decomposition.
R. S. Assary, J. Lu, X. Luo, X. Zhang, Y. Ren, H. Wu, H. M. Albishri, D. A. El-Hady, A. S. Al-Bogami, L. A. Curtiss,* K. Amine*
Flexible capacity: A new nitrogendoped well-ordered mesoporous carbon synthesized by a direct organic–inorganic coassembly method exhibits a high surface area, large pore size, and high capacitance in 1 mol L 1 H2SO4 aqueous electrolytes (see picture).
Y. Song, L. Li, Y. Wang, C. Wang, Z. Guo, Y. Xia*
Something to lean on: The electrocatalytic properties of platinum nanoparticles (NPs, see picture) supported by carbon-surrounded TiOx show enhanced oxygen reduction reaction activity and selectivity compared with pure carbonsupported ones. The chosen synthetic route allows facile deposition of thin carbon films for increased conductivity.
C. Gebauer, Z. Jusys, M. Wassner, N. Hsing, R. J. Behm*
Genesis of hydrogen peroxide: Rotating ring disc electrode studies combined with kinetic modeling show that transition-metal cations of perovskite oxides mediate the chemical and electrochemical steps of the oxygen reduction reaction through a series pathway. Escape of HO2 depends on the nature and loading of the oxide and on the presence of carbon; the latter affecting the formation of HO2 and the utilization of oxide.
T. Poux, A. Bonnefont, G. Kranguven, G. A. Tsirlina, E. R. Savinova*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2077 – 2083 Molecular-Level Insights into the Reactivity of Siloxane-Based Electrolytes at a Lithium-Metal Anode
2084 – 2093 Nitrogen-Doped Ordered Mesoporous Carbon with a High Surface Area, Synthesized through Organic– Inorganic Coassembly, and Its Application in Supercapacitors
2094 – 2107 Membrane Fuel Cell Cathode Catalysts Based on Titanium Oxide Supported Platinum Nanoparticles
2108 – 2120 Electrocatalytic Oxygen Reduction Reaction on Perovskite Oxides: Series versus Direct Pathway
1911
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
S. Hartung, N. Bucher, V. S. Nair, C. Y. Ling, Y. Wang, H. E. Hoster, M. Srinivasan*
The battery performance of sodium vanadium oxide (NVO) is tested in sodium-ion-battery half cells. X-ray photoelectron spectroscopy measurements aid in the study of the electrochemical process. NVO exhibits high capacities when used as a cathode material, even at current rates as high as 800 mA g 1. Symmetric full-cell batteries with varying cathode:anode mass ratios are also studied.
2121 – 2128 Sodium Vanadium Oxide: A New Material for High-Performance Symmetric Sodium-Ion Batteries
S. Krishnamurthy, P. V. Kamat*
Rainbow CdSe–GO composites: Electron-transfer rates from CdSe quantum dots into graphene oxide (GO) are dependent on the particle size of CdSe. A sequential arrangement of a “rainbow solar cell” and incorporating GO makes it possible to modulate the photoresponse in photoelectrochemical solar cells. Superior photoconversion efficiency is attributed to improved charge separation in the composite assembly resulting from GO.
2129 – 2135 CdSe–Graphene Oxide LightHarvesting Assembly: Size-Dependent Electron Transfer and Light Energy Conversion Aspects
Y. Luo, A. Habrioux, L. Calvillo, G. Granozzi, N. Alonso-Vante*
Carbon-supported nanoparticles (NPs) are synthesized by a water-in-oil chemical route. The Y- and Gd-modified Pt NPs show an enhanced electrocatalytic activity for the oxygen reduction reaction (ORR). X-ray diffraction and X-ray photoelectron spectroscopy studies reveal no evidence of alloy formation. The enhancement of the ORR kinetics on Pt-Y/C and heat-treated Pt-Gd/C catalysts could be associated with the surface modification of Pt NPs by rareearth-element oxides.
2136 – 2144 Yttrium Oxide/Gadolinium OxideModified Platinum Nanoparticles as Cathodes for the Oxygen Reduction Reaction
Y. Handa, K. Yamagiwa, Y. Ikeda, Y. Yanagisawa, S. Watanabe, N. Yabuuchi, S. Komaba* 2145 – 2151 Fabrication of Carbon-Felt-Based Multi-Enzyme Immobilized Anodes to Oxidize Sucrose for Biofuel Cells
Multi-Enzyme Bioanodes: The combination of four enzymes in an electrode enables the use of sucrose as a fuel in biofuel cells. A sucrose/O2 device fabri 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
cated using this new bioanode can be operated in commercially available beverages containing sugar as “biofuel”.
ChemPhysChem 2014, 15, 1907 – 1914
1912
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
Matching sodium olivine and tin: An electrochemically converted NaFePO4 olivine cathode and a nanostructured Sn–C anode are combined in an efficient, sodium-ion battery, characterized by a capacity of 150 mAh g 1, a voltage of 3 V and, consequently, a practical energy density estimated to be of the order of 150 Wh kg 1
I. Hasa, J. Hassoun,* Y.-K. Sun, B. Scrosati*
Size matters! Particle-size effects on the entropy behavior of a LixFePO4 electrode are studied by electrochemical calorimetry and potentiometric measurements. Under open-circuit conditions, the LixFePO4 particles equilibrate into either a kinetically metastable state or a thermodynamically stable state depending on the particle size.
K. Kai, Y. Kobayashi, H. Miyashiro, G. Oyama, S.-i. Nishimura, M. Okubo, A. Yamada*
An asymmetric supercapacitor with activated carbon as positive electrode and Na6V10O28 as negative electrode in Li + containing organic electrolyte is fabricated and exhibits a high energy density of 73 Wh kg 1 with a power density of 312 W kg 1. The picture shows the proposed Li + intercalation and/or adsorption process in the Na6V10O28 ACHTUNGREelectrodes.
H.-Y. Chen , G. Wee , R. Al-Oweini, J. Friedl , K. S. Tan, Y. Wang, C. L. Wong , U. Kortz, U. Stimming ,* M. Srinivasan *
Continuously rechargeable electrodes: The borohydride oxidation reaction in alkaline media is studied using metal hydride alloys formed by LaNi4.7Sn0.2Cu0.1 and LaNi4.78Al0.22, chemically modified with platinum, palladium, and gold deposits. Hydrolysis of the borohydride ions as well as continuous hydriding of the alloys are confirmed when the materials are exposed to BH4 .
W. J. Paschoalino, S. J. Thompson, A. E. Russell, E. A. Ticianelli*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2152 – 2155 Sodium-Ion Battery based on an Electrochemically Converted NaFePO4 Cathode and Nanostructured Tin– Carbon Anode
2156 – 2161 Particle-Size Effects on the Entropy Behavior of a LixFePO4 Electrode
2162 – 2169 A Polyoxovanadate as an Advanced Electrode Material for Supercapacitors
2170 – 2176 The Borohydride Oxidation Reaction on La–Ni-Based Hydrogen-Storage Alloys
1913
CHEMPHYSCHEM CONTENTS D. Bresser, E. Paillard,* P. Niehoff, S. Krueger, F. Mueller, M. Winter, S. Passerini* 2177 – 2185 Challenges of “Going Nano”: Enhanced Electrochemical Performance of Cobalt Oxide Nanoparticles by Carbothermal Reduction and In Situ Carbon Coating
Supporting Information on www.chemphyschem.org (see article for access details). This is an open-access article, published under the terms and conditions of a Creative Commons license; the specific license and details about the permitted reuse can be found on the first page of the article.
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemphyschem.org Not just a carbon layer! Carbon coating of an active electrode material based on cobalt oxide reduces the impact of electrolyte decomposition and enhances the electronic conductivity within the electrode material composite, which results in a substantial improvement of the cycling stability and coulombic efficiency. This aspect is particularly important for high-surface-area, transition-metal-oxide nanomaterials, herein proposed as advantageous alternative lithium-ion anodes. A video clip is available as Supporting Information on the WWW (see article for access details). * Author to whom correspondence should be addressed.
ChemPhysChem 2014, 15, 1907 – 1914
1914
COVER PICTURE The picture shows a snapshot from a molecular dynamics simulation, presented on p. 2003 by W. Schmickler et al. for OH adsorbed on Pt(111) from an aqueous solution. The OH can be seen on the left with a red oxygen and a green hydrogen atom. Superimposed is a free energy surface for the reaction showing the adsorbed OH on the left, a chemisorbed OH in the center, and a solvated OH at the right.
NEWS Spotlights on our sister journals
1918 – 1921
REVIEWS The importance of the chemical history of the electrode surface before electrochemical cycling as well as the correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior of LiFePO4 and LiNi1/2Mn1/2O2 electrodes are investigated by magic-angle-spinning nuclear magnetic resonance, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. These techniques allow the study of interface aging and failure mechanisms.
N. Dupr,* M. Cuisinier, J.-F. Martin, D. Guyomard
Danger, high voltage! LiNi0.5Mn1.5O4 high-voltage spinel is a promising candidate for next-generation cathode materials, but its commercialization is hampered by electrolyte instability and concurrent parasitic reactions at electrode/ electrolyte interfaces (see figure). The known challenges in LiNi0.5Mn1.5O4/ graphite full-cell systems are reviewed. In addition, multiple strategies to overcome the issues and prolong the cycle life of full cells are introduced.
J.-H. Kim,* N. P. W. Pieczonka, L. Yang
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1922 – 1938 Interphase Evolution at Two Promising Electrode Materials for Li-Ion Batteries: LiFePO4 and LiNi1/2Mn1/2O2
1940 – 1954 Challenges and Approaches for HighVoltage Spinel Lithium-Ion Batteries
ChemPhysChem 2014, 15, 1907 – 1914
1907
CHEMPHYSCHEM CONTENTS S. Tan, Y. J. Ji, Z. R. Zhang, Y. Yang* 1956 – 1969 Recent Progress in Research on HighVoltage Electrolytes for Lithium-Ion Batteries
www.chemphyschem.org Safe and stable: Developing a stable and safe electrolyte that works at high voltages is a formidable challenge in present Li-ion-battery research. Recent progress in the development of several promising high-voltage electrolyte systems is summarized and reviewed.
MINIREVIEWS S. Ha , J.-K. Kim , A. Choi, Y. Kim,* K. T. Lee* 1971 – 1982 Sodium–Metal Halide and Sodium–Air Batteries
L. M. Peter,* K. G. Upul Wijayantha* 1983 – 1995 Photoelectrochemical Water Splitting at Semiconductor Electrodes: Fundamental Problems and New Perspectives
Power sauce: Sodium batteries such as Na–metal halide (see picture) and Na–air batteries are considered to be promising for use in electric vehicles owing to good safety and high energy density. This Minireview provides an overview of the fundamentals of and recent progress in the fields of Na– metal halide and Na–air batteries, with the aim of providing a better understanding of new electrochemical systems. Artificial photosynthesis—the generation of chemical fuels from water and sunlight—is one of the key scientific challenges for the 21st century. This review takes a closer look at recent progress in the field of light-driven water splitting at semiconductor electrodes and highlights some of the current bottlenecks that need to be addressed if dreams are to become reality.
COMMUNICATIONS R. A. Martnez-Rodrguez, F. J. Vidal-Iglesias, J. Solla-Gulln, C. R. Cabrera, J. M. Feliu* 1997 – 2001 Synthesis and Electrocatalytic Properties of H2SO4-Induced (100) Pt Nanoparticles Prepared in Water-in-Oil Microemulsion
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Shapewear for nanoparticles: Sulfuric acid is used as a surface modifier to synthesize (100) Pt nanoparticles (NPs) by using a water-in-oil microemulsion method. The electrocatalytic properties of the resulting cubic-like Pt NPs are evaluated towards ammonia and CO electro-oxidations.
ChemPhysChem 2014, 15, 1907 – 1914
1908
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
ARTICLES An adsorbed fraction of water: Adsorption of the hydroxyl ion has been studied by a formalism that combines DFT with molecular dynamics (see figure). The results suggest that OH can be adsorbed on PtACHTUNGRE(111) either as a metastable, physisorbed ion or as a chemisorbed radical. The energy of activation is of the order of 0.6 eV, so the adsorption is fast.
L. M. C. Pinto, P. Quaino, M. D. Arce, E. Santos, W. Schmickler*
Top of the PECs: N-doped reduced graphene oxide (nRGO) is systematically incorporated into the photoanode, cathode, and redox electrolyte of a photoelectrochemical cell and was shown to favorably influence the cell performance.
J. Selvaraj, S. Gupta, S. DelaCruz, V. Subramanian*
Inverted reactivity order: Ethanol oxidation on platinum single-crystal electrodes in alkaline solutions produces mainly acetate and the activity order is the opposite of that found in acid solutions. The formation of acetaldehyde deactivates the surface (see picture).
C. Bus-Rogero, E. Herrero,* J. M. Feliu
Methanol adsorption rate: At Pt electrodes, methanol is oxidized either to dissolved intermediates or—in parallel—to CO2 via adsorbed CO. The adsorption rate of methanol is dependent on the surface structure and increases with the step density. A further increase is observed upon step decoration by Ru.
E. Mostafa, A. A. Abd-El-Latif, H. Baltruschat*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2003 – 2009 Electrochemical Adsorption of OH on PtACHTUNGRE(111) in Alkaline Solutions: Combining DFT and Molecular Dynamics
2010 – 2018 Role of Reduced Graphene Oxide in the Critical Components of a CdSSensitized TiO2-Based Photoelectrochemical Cell
2019 – 2028 Ethanol Oxidation on Pt Single-Crystal Electrodes: Surface-Structure Effects in Alkaline Medium
2029 – 2043 Electrocatalytic Oxidation and Adsorption Rate of Methanol at Pt Stepped Single-Crystal Electrodes and Effect of Ru Step Decoration: A DEMS Study
1909
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
G. A. Attard,* A. Brew, J.-Y. Ye, D. Morgan, S.-G. Sun 2044 – 2051 Oxygen Reduction Reaction Activity on PtACHTUNGRE{111} Surface Alloys PtM overlayers (M = Fe, Co or Ni) supported on a PtACHTUNGRE{111} electrode are prepared via thermal annealing of aqueous droplets containing MZ + cations directly attached to the electrode. When a hydrogen ambient is used for thermal an-
N. Myung,* W. Lee, C. Lee, S. Jeong, K. Rajeshwar*
nealing, highly active oxygen reduction electrocatalysts are formed. A positive potential shift in PtM oxide formation is seen compared to PtACHTUNGRE{111}, which correlates with increased oxygen reduction reaction activity.
Bismuth vanadate and gold-modified bismuth vanadate are synthesized for the first time by a two-step anodic electrodeposition-galvanic replacement hybrid scheme. The metal-modified sample shows higher visible-light absorption, higher anodic photocurrent, and superior photocatalytic activity relative to the virgin sample.
2052 – 2057 Synthesis of Au-BiVO4 Nanocomposite through Anodic Electrodeposition Followed by Galvanic Replacement and Its Application to the Photocatalytic Decomposition of Methyl Orange
N. G. Hçrmann, A. Groß*
A polar exploration: An expression is derived that describes the effect of electron transfer between two exposed polar surfaces due to the internal electric field generated by the surfaces. This expression is applied to Li2FeSiO4, which is of interest as a possible electrode material for future Li-ion batteries.
2058 – 2069 Polar Surface Energies of IonoCovalent Materials: Implications of a Charge-Transfer Model Tested on Li2FeSiO4 Surfaces
J. Ming, W.-J. Kwak, J.-B. Park, C.-D. Shin, J. Lu, L. Curtiss, K. Amine,* Y.-K. Sun* 2070 – 2076 A Physical Pulverization Strategy for Preparing a Highly Active Composite of CoOx and Crushed Graphite for Lithium–Oxygen Batteries
Taking a beating: A new physical pulverization strategy has been developed to prepare a highly active composite of
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
CoOx/crushed graphite for the cathode in lithium–oxygen batteries.
ChemPhysChem 2014, 15, 1907 – 1914
1910
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
Experimental and computational techniques are applied to explore the reactivity of tri(ethylene glycol)-substituted trimethylsilane, a siloxane-based ether electrolyte, at a lithium-metal anode. The study indicates that both protection of the lithium metal and prevention of oxygen crossover to the anode are essential for minimizing electrolyte and anode decomposition.
R. S. Assary, J. Lu, X. Luo, X. Zhang, Y. Ren, H. Wu, H. M. Albishri, D. A. El-Hady, A. S. Al-Bogami, L. A. Curtiss,* K. Amine*
Flexible capacity: A new nitrogendoped well-ordered mesoporous carbon synthesized by a direct organic–inorganic coassembly method exhibits a high surface area, large pore size, and high capacitance in 1 mol L 1 H2SO4 aqueous electrolytes (see picture).
Y. Song, L. Li, Y. Wang, C. Wang, Z. Guo, Y. Xia*
Something to lean on: The electrocatalytic properties of platinum nanoparticles (NPs, see picture) supported by carbon-surrounded TiOx show enhanced oxygen reduction reaction activity and selectivity compared with pure carbonsupported ones. The chosen synthetic route allows facile deposition of thin carbon films for increased conductivity.
C. Gebauer, Z. Jusys, M. Wassner, N. Hsing, R. J. Behm*
Genesis of hydrogen peroxide: Rotating ring disc electrode studies combined with kinetic modeling show that transition-metal cations of perovskite oxides mediate the chemical and electrochemical steps of the oxygen reduction reaction through a series pathway. Escape of HO2 depends on the nature and loading of the oxide and on the presence of carbon; the latter affecting the formation of HO2 and the utilization of oxide.
T. Poux, A. Bonnefont, G. Kranguven, G. A. Tsirlina, E. R. Savinova*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2077 – 2083 Molecular-Level Insights into the Reactivity of Siloxane-Based Electrolytes at a Lithium-Metal Anode
2084 – 2093 Nitrogen-Doped Ordered Mesoporous Carbon with a High Surface Area, Synthesized through Organic– Inorganic Coassembly, and Its Application in Supercapacitors
2094 – 2107 Membrane Fuel Cell Cathode Catalysts Based on Titanium Oxide Supported Platinum Nanoparticles
2108 – 2120 Electrocatalytic Oxygen Reduction Reaction on Perovskite Oxides: Series versus Direct Pathway
1911
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
S. Hartung, N. Bucher, V. S. Nair, C. Y. Ling, Y. Wang, H. E. Hoster, M. Srinivasan*
The battery performance of sodium vanadium oxide (NVO) is tested in sodium-ion-battery half cells. X-ray photoelectron spectroscopy measurements aid in the study of the electrochemical process. NVO exhibits high capacities when used as a cathode material, even at current rates as high as 800 mA g 1. Symmetric full-cell batteries with varying cathode:anode mass ratios are also studied.
2121 – 2128 Sodium Vanadium Oxide: A New Material for High-Performance Symmetric Sodium-Ion Batteries
S. Krishnamurthy, P. V. Kamat*
Rainbow CdSe–GO composites: Electron-transfer rates from CdSe quantum dots into graphene oxide (GO) are dependent on the particle size of CdSe. A sequential arrangement of a “rainbow solar cell” and incorporating GO makes it possible to modulate the photoresponse in photoelectrochemical solar cells. Superior photoconversion efficiency is attributed to improved charge separation in the composite assembly resulting from GO.
2129 – 2135 CdSe–Graphene Oxide LightHarvesting Assembly: Size-Dependent Electron Transfer and Light Energy Conversion Aspects
Y. Luo, A. Habrioux, L. Calvillo, G. Granozzi, N. Alonso-Vante*
Carbon-supported nanoparticles (NPs) are synthesized by a water-in-oil chemical route. The Y- and Gd-modified Pt NPs show an enhanced electrocatalytic activity for the oxygen reduction reaction (ORR). X-ray diffraction and X-ray photoelectron spectroscopy studies reveal no evidence of alloy formation. The enhancement of the ORR kinetics on Pt-Y/C and heat-treated Pt-Gd/C catalysts could be associated with the surface modification of Pt NPs by rareearth-element oxides.
2136 – 2144 Yttrium Oxide/Gadolinium OxideModified Platinum Nanoparticles as Cathodes for the Oxygen Reduction Reaction
Y. Handa, K. Yamagiwa, Y. Ikeda, Y. Yanagisawa, S. Watanabe, N. Yabuuchi, S. Komaba* 2145 – 2151 Fabrication of Carbon-Felt-Based Multi-Enzyme Immobilized Anodes to Oxidize Sucrose for Biofuel Cells
Multi-Enzyme Bioanodes: The combination of four enzymes in an electrode enables the use of sucrose as a fuel in biofuel cells. A sucrose/O2 device fabri 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
cated using this new bioanode can be operated in commercially available beverages containing sugar as “biofuel”.
ChemPhysChem 2014, 15, 1907 – 1914
1912
CHEMPHYSCHEM CONTENTS
www.chemphyschem.org
Matching sodium olivine and tin: An electrochemically converted NaFePO4 olivine cathode and a nanostructured Sn–C anode are combined in an efficient, sodium-ion battery, characterized by a capacity of 150 mAh g 1, a voltage of 3 V and, consequently, a practical energy density estimated to be of the order of 150 Wh kg 1
I. Hasa, J. Hassoun,* Y.-K. Sun, B. Scrosati*
Size matters! Particle-size effects on the entropy behavior of a LixFePO4 electrode are studied by electrochemical calorimetry and potentiometric measurements. Under open-circuit conditions, the LixFePO4 particles equilibrate into either a kinetically metastable state or a thermodynamically stable state depending on the particle size.
K. Kai, Y. Kobayashi, H. Miyashiro, G. Oyama, S.-i. Nishimura, M. Okubo, A. Yamada*
An asymmetric supercapacitor with activated carbon as positive electrode and Na6V10O28 as negative electrode in Li + containing organic electrolyte is fabricated and exhibits a high energy density of 73 Wh kg 1 with a power density of 312 W kg 1. The picture shows the proposed Li + intercalation and/or adsorption process in the Na6V10O28 ACHTUNGREelectrodes.
H.-Y. Chen , G. Wee , R. Al-Oweini, J. Friedl , K. S. Tan, Y. Wang, C. L. Wong , U. Kortz, U. Stimming ,* M. Srinivasan *
Continuously rechargeable electrodes: The borohydride oxidation reaction in alkaline media is studied using metal hydride alloys formed by LaNi4.7Sn0.2Cu0.1 and LaNi4.78Al0.22, chemically modified with platinum, palladium, and gold deposits. Hydrolysis of the borohydride ions as well as continuous hydriding of the alloys are confirmed when the materials are exposed to BH4 .
W. J. Paschoalino, S. J. Thompson, A. E. Russell, E. A. Ticianelli*
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemPhysChem 2014, 15, 1907 – 1914
2152 – 2155 Sodium-Ion Battery based on an Electrochemically Converted NaFePO4 Cathode and Nanostructured Tin– Carbon Anode
2156 – 2161 Particle-Size Effects on the Entropy Behavior of a LixFePO4 Electrode
2162 – 2169 A Polyoxovanadate as an Advanced Electrode Material for Supercapacitors
2170 – 2176 The Borohydride Oxidation Reaction on La–Ni-Based Hydrogen-Storage Alloys
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CHEMPHYSCHEM CONTENTS D. Bresser, E. Paillard,* P. Niehoff, S. Krueger, F. Mueller, M. Winter, S. Passerini* 2177 – 2185 Challenges of “Going Nano”: Enhanced Electrochemical Performance of Cobalt Oxide Nanoparticles by Carbothermal Reduction and In Situ Carbon Coating
Supporting Information on www.chemphyschem.org (see article for access details). This is an open-access article, published under the terms and conditions of a Creative Commons license; the specific license and details about the permitted reuse can be found on the first page of the article.
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemphyschem.org Not just a carbon layer! Carbon coating of an active electrode material based on cobalt oxide reduces the impact of electrolyte decomposition and enhances the electronic conductivity within the electrode material composite, which results in a substantial improvement of the cycling stability and coulombic efficiency. This aspect is particularly important for high-surface-area, transition-metal-oxide nanomaterials, herein proposed as advantageous alternative lithium-ion anodes. A video clip is available as Supporting Information on the WWW (see article for access details). * Author to whom correspondence should be addressed.
ChemPhysChem 2014, 15, 1907 – 1914
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