Electrochemical and electron microscopic characterization of Super-P based cathodes for Li–O₂ batteries

• Mario Marinaro,
• Santhana K. Eswara Moorthy,
• Jörg Bernhard,
• Ludwig Jörissen,
• Margret Wohlfahrt-Mehrens and
• Ute Kaiser

Beilstein J. Nanotechnol. 2013, 4, 665–670, doi:10.3762/bjnano.4.74

• a stepwise fashion leading to the formation of LiO2 and Li2O2 as shown in the chemical reactions below. Conversely, upon charging, the oxygen evolution reaction (OER) gives O2 and Li+ back via a 2-electrons reaction. The unsuitability of commonly used electrolytes for Li-ion batteries (e.g

• charge–discharge cycles) of the Li–O2 cells [10][15]. The shape of the galvanostatic curve is characterized by a flat discharge plateau at ≈2.7 V, whereas upon charging the potential of the cell rapidly increases to 3.2 V, then proceeding up to 3.9 V in a sloped manner and finally approaching the end of

• charge-transfer resistance. The observed behavior can be explained on the basis of a growing insulating phase at the cathode side and more specifically directly related to the formation of Li2O2 upon discharge, as demonstrated by the XRD results that will be discussed later on. After charging (Figure 2

Preparation of electrochemically active silicon nanotubes in highly ordered arrays

• Tobias Grünzel,
• Young Joo Lee,
• Karsten Kuepper and
• Julien Bachmann

Beilstein J. Nanotechnol. 2013, 4, 655–664, doi:10.3762/bjnano.4.73

• with Li, and which are associated with the concomitant phase transitions, severely constraint the practical exploitation of this very large capacity [5]. In bulk silicon, one does not limit oneself to charging and discharging a small fraction of the theoretically available lithium, the mechanical

• electrolyte to the vicinity of the current collector should allow for a ‘lateral’ expansion of the electrode material upon charging, whereas direct ‘vertical’ transport paths are maintained for the charge carriers in the solid electrode (for the electrons) and in the electrolyte (for the Li+ ions). The

• in a Li+-containing electrolyte. The cyclic voltammetry of the lithium/silicon system is typically characterized by a sharp reduction between +0.1 and +0.2 V (vs Li/Li+) on the charging curve and a broader double oxidation peak situated between +0.3 and +0.7 V upon discharge [6][7][8]. Upon inclusion

AFM as an analysis tool for high-capacity sulfur cathodes for Li–S batteries

• Renate Hiesgen,
• Seniz Sörgel,
• Rémi Costa,
• Linus Carlé,
• Ines Galm,
• Natalia Cañas,
• Brigitta Pascucci and
• K. Andreas Friedrich

Beilstein J. Nanotechnol. 2013, 4, 611–624, doi:10.3762/bjnano.4.68

• battery, which depends mainly on the type of binder that is used [5][6][7]. Related to the morphology and volume changes of the cathodes, it was found that the sulfur cathodes expand while discharging and shrink while charging. The thickness change of the electrode was measured to be approximately 22% [8

• present in most parts of the surface with high stiffness. These transient currents indicated surface regions where fast charging processes occurred even before contact of that sample to lithium species. Therefore, the transients were not associated with an ionic charging process. An electronic charge

• transfer is present and a charging of carbon agglomerates on insulating sulfur particles (indicated by the high stiffness of this region) with the tip is assumed. The size of the underlying sulfur particles retrieved from the high stiffness region is about 0.5 µm and presumably they are too large for a

Novel composite Zr/PBI-O-PhT membranes for HT-PEFC applications

• Mikhail S. Kondratenko,
• Igor I. Ponomarev,
• Marat O. Gallyamov,
• Dmitry Y. Razorenov,
• Yulia A. Volkova,
• Elena P. Kharitonova and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2013, 4, 481–492, doi:10.3762/bjnano.4.57

• of the AL and models the following processes: charge-transfer during the oxygen reduction reaction, double layer charging and ohmic losses due to finite proton conductivity of the AL. The following parameters were obtained as a result of the impedance spectra approximation: the undistributed ohmic

In situ monitoring magnetism and resistance of nanophase platinum upon electrochemical oxidation

• Eva-Maria Steyskal,
• Stefan Topolovec,
• Stephan Landgraf,
• Heinz Krenn and
• Roland Würschum

Beilstein J. Nanotechnol. 2013, 4, 394–399, doi:10.3762/bjnano.4.46

• amount of deposited oxygen, is considered to be primarily caused by charge-carrier scattering processes at the metal–electrolyte interfaces. In comparison, the decrease of the magnetic moment upon positive charging appears to be governed by the electric field at the nanocrystallite–electrolyte interfaces

• combination to provide a deeper understanding of the underlying charge-related processes since both properties are expected to respond differently on charging and chemical modification. The studies make use of a specifically designed electrochemical cell that allows in situ magnetic studies in a SQUID

• contacts similar to our previous work [5], improved by adding a fifth wire providing an independent contact for electrochemical charging (further referred to as sample PtER). For magnetic measurements, 17.8 mg of the powder were compacted to a cylindrical pellet, which was carefully wrapped by a gold wire

Influence of the solvent on the stability of bis(terpyridine) structures on graphite

• Daniela Künzel and
• Axel Groß

Beilstein J. Nanotechnol. 2013, 4, 269–277, doi:10.3762/bjnano.4.29

• ultrafine settings of the program. Partial charges of the atoms are assigned with the Gasteiger [25] and QEq [26] methods for UFF and Dreiding, whereas charging methods are already included in the CVFF and Compass force fields. As mentioned in the introduction, the theoretical treatment of liquids requires

• molecular dynamics trajectory range from 0.07 g/cm3 for UFF with Gasteiger charging, up to 1.01 g/cm3 for Dreiding with QEq charges. A value of 0.997 g/cm3 would have been expected [33]. With UFF, the deviation from the experiment is particularly high with both charging methods. Dreiding performs well with

• QEq charging, but not with Gasteiger charges. Compass and CVFF also show a deviation from experimental values of less than 5%. Further Compass calculations with varying system size could show that the solvent density does not change noticeably over a wide range of system sizes. Starting from a system

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• used, and inversely when charging. Their current limitation comes from their poor performance in terms of energy and power densities, safety and lifetime. Much attention is focused on the electrodes and electrolyte technology. Lu et al. [101] developed vertically aligned carbon nanotubes with and

Low-dose patterning of platinum nanoclusters on carbon nanotubes by focused-electron-beam-induced deposition as studied by TEM

• Xiaoxing Ke,
• Carla Bittencourt,
• Sara Bals and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2013, 4, 77–86, doi:10.3762/bjnano.4.9

• leaves the rest of the CNT unaffected (Figure 3b). The unwanted proximity effect, which is noted to be related to a large dose and charging of the surface [12][34][35], is not seen at this scale. In fact, in this study a low dose is used and the CNTs have an “electron-transparent” thickness, thus the

Structural and electronic properties of oligo- and polythiophenes modified by substituents

• Simon P. Rittmeyer and
• Axel Groß

Beilstein J. Nanotechnol. 2012, 3, 909–919, doi:10.3762/bjnano.3.101

• conjugation to the nitro group and therefore to lengthen the respective bond. This could be a reason for the observed distortions of the polymer structure. Regarding the density of states of the oxidized polymers plotted in Figure 11, it is obvious that positively charging the polymers leads to a partially

• occupied valence band, whereas the band structure is hardly changed compared to the neutral polymers. This indicates that charging the polymers basically corresponds to a shift of the Fermi energy without significant changes in the band structure and leads to metallic behavior. The substituted polymers, in

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• charging occurs (i.e., the level alignment remains the same), one should expect the frontier orbital to be located closer to EF. However, this observation is in partial disagreement with the findings of Kim et al. who found the values 0.6 eV (closed form) and 0.41 eV (open form) at low temperatures [32

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• inside a grain. Due to the tunnel-coupling between the grains the one-electron energy levels at the chemical potential are broadened. This effect is expressed by the broadening parameter Γ = gδ. Another important parameter is the single-grain Coulomb charging energy EC = e2/2C where C r is the

• capacitance of the grain. EC is equal to the change in electrostatic energy of the grain when one electron is added or removed. For insulating samples charge transport is suppressed at low temperatures due to this charging energy. The average level spacing δ can become larger than the charging energy only for

• levels of the coupled grains with indices (i, j). The Coulomb charging energy is expressed through the capacitive coupling Cij between the grains denotes the electron number operator as the difference from the charge neutral state with N electrons per grain By means of field-theoretical methods

A facile approach to nanoarchitectured three-dimensional graphene-based Li–Mn–O composite as high-power cathodes for Li-ion batteries

• Wenyu Zhang,
• Yi Zeng,
• Chen Xu,
• Ni Xiao,
• Yiben Gao,
• Lain-Jong Li,
• Xiaodong Chen,
• Huey Hoon Hng and
• Qingyu Yan

Beilstein J. Nanotechnol. 2012, 3, 513–523, doi:10.3762/bjnano.3.59

• and 17.04 kW·kg−1, respectively, during the 300th cycle. Here, it is worth pointing out that the charge rate is chosen as 19.00 C (2812.5 mA·g−1) to mimic the fast battery charging process. In fact, some reports on the rate capabilities of cathode materials use a high discharge C rate and a low charge

• C rate, which are different from the really fast battery charging process, especially for plug-in electric vehicles. For LMO/G electrodes with ILMO:G = 2.00 and 4.49, the cycling responses under similar testing parameters, e.g., a discharge current density of 5625 mA·g−1 (38.01 C) and a charge

The morphology of silver nanoparticles prepared by enzyme-induced reduction

• Henrik Schneidewind,
• Thomas Schüler,
• Katharina K. Strelau,
• Karina Weber,
• Dana Cialla,
• Marco Diegel,
• Roland Mattheis,
• Andreas Berger,
• Robert Möller and
• Jürgen Popp

Beilstein J. Nanotechnol. 2012, 3, 404–414, doi:10.3762/bjnano.3.47

• glass or silicon substrates. The silicon substrates, which were used for the RBS investigations in order to avoid any electrical charging during analysis, were covered by a natural oxide layer. The coarse cleaning of the substrates was performed in an ultrasonic bath in acetone, ethanol, and water (for

Transmission eigenvalue distributions in highly conductive molecular junctions

• Justin P. Bergfield,
• Joshua D. Barr and
• Charles A. Stafford

Beilstein J. Nanotechnol. 2012, 3, 40–51, doi:10.3762/bjnano.3.5

• position of the chemical potential of the leads relative to the molecular energy levels and the large charging energy of small molecules, transport in SMJs is typically dominated by individual molecular resonances. In this subsection, we calculate the Green’s function in the isolated-resonance

• the nearest carbon atom [14]. The average over the interaction matrix elements defines the “charging energy” of the molecule in the junction [14]. The charging energy and per-orbital Tr{Γ} distributions are shown in the top and bottom panels of Figure 5, respectively, in which two electrodes are

• used in all calculations. As indicated by the figure, the Tr{Γ}/6 distribution is roughly four times as broad as the charging-energy distribution. This fact justifies the use of the ensemble-average matrix for transport calculations [2], an approximation which makes the calculation of thousands of

When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

• Gemma C. Solomon,
• Justin P. Bergfield,
• Charles A. Stafford and
• Mark A. Ratner

Beilstein J. Nanotechnol. 2011, 2, 862–871, doi:10.3762/bjnano.2.95

• in which the electrode–molecule coupling is on the order of the molecule’s charging energy. In this regime, the transport exhibits many nonperturbative effects (e.g., simultaneous charge quantization and quantum interference [34]) that cannot be properly described unless the processes are considered

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

• the metallic micro-islands were denser than monolayers chemisorbed on TiO2 substrates that had no metallic islands. Results were explained in terms of charging effects [18]. That charging of the substrate may affect the chemisorption of organosiloxane monolayers can be deduced also from a comparison

Approaches to nanostructure control and functionalizations of polymer@silica hybrid nanograss generated by biomimetic silica mineralization on a self-assembled polyamine layer

• Jian-Jun Yuan and
• Ren-Hua Jin

Beilstein J. Nanotechnol. 2011, 2, 760–773, doi:10.3762/bjnano.2.84

• tube was used as a representative substrate for the nanograss generation. Figure 1 demonstrates our process for the generation of a LPEI@silica hybrid nanograss film on a substrate surface. Our process involves i) charging the LPEI hot solution into the tube; ii) pushing out the excess hot LPEI

• prepared by dissolving LPEI powder into water at 80 °C. The assembly of a LPEI layer on the inner surface of the tubes was simply achieved by first charging the hot aqueous solution of LPEI into the tube, and then by removal of the excess hot solution from the tube immediately, to leave a tube with the

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• magnetic energy contribution [37] that controls their domain wall structure and magnetization reversal process [38]. As we were using a semiconductor material as a substrate, we expected that some charging effects would appear where the electron beam was scanned. The secondary electrons generated when the

Charge transfer through single molecule contacts: How reliable are rate descriptions?

• Denis Kast,
• L. Kecke and
• J. Ankerhold

Beilstein J. Nanotechnol. 2011, 2, 416–426, doi:10.3762/bjnano.2.47

• + l0q)2. Now, the presence of the leads acts (for finite voltages) as an external driving force alternately charging (q = 1) and discharging (q = 0) the dot, thus switching alternately between V0 and V1 for the phonon mode. The classical energy needed to reorganize the phonon is the so-called

Simulation of bonding effects in HRTEM images of light element materials

• Simon Kurasch,
• Jannik C. Meyer,
• Daniela Künzel,
• Axel Groß and
• Ute Kaiser

Beilstein J. Nanotechnol. 2011, 2, 394–404, doi:10.3762/bjnano.2.45

• the inverse. However, the implication on the final TEM image is not very intuitive because it depends on the absolute potential values: For nitrogen, the increase of the contrast due to charging enables the detection whereas for oxygen this increase disables the detection. On the contrary, the

Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

• Michael Roos,
• Benedikt Uhl,
• Daniela Künzel,
• Harry E. Hoster,
• Axel Groß and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 365–373, doi:10.3762/bjnano.2.42

• “hill” position does not correspond to a true local minimum, so the structure optimization was performed for the internal molecular degrees of freedom with the center of mass of the molecule being on top of the hill. For Dreiding and UFF, we applied both the Gasteiger [44] and the QEq charging method

Switching adhesion forces by crossing the metal–insulator transition in Magnéli-type vanadium oxide crystals

• Bert Stegemann,
• Matthias Klemm,
• Siegfried Horn and
• Mathias Woydt

Beilstein J. Nanotechnol. 2011, 2, 59–65, doi:10.3762/bjnano.2.8

• contribution of the overall adhesion force. However, reference measurements with a silica microsphere on V3O5 showed the same qualitative behavior, i.e., a lower adhesion force in the metallic state. Accordingly, a possible tip-induced electrostatic contact charging is negligible. Conclusion The adhesion

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• considered as a capacitor, resulting in the following equation for the electrostatic energy Eel, which together with the non-electrostatic interaction such as a Lennard-Jones potential adds to the total energy, [18][19] Echarge is the energy due to electrostatic charging and EVS is the work done by the

Precursor concentration and temperature controlled formation of polyvinyl alcohol-capped CdSe-quantum dots

• Chetan P. Shah,
• Madhabchandra Rath,
• Manmohan Kumar and
• Parma N. Bajaj

Beilstein J. Nanotechnol. 2010, 1, 119–127, doi:10.3762/bjnano.1.14

• Figure 9. TEM measurements could not be carried out in the presence of PVA, because of charging of the sample due to its non-conducting nature. Therefore, PVA was removed, before loading the sample on the copper grid, which led to aggregation of the individual nanoparticles during drying of the sample