@article{7293, abstract = {If proton exchange membrane fuel cells (PEMFC) are ever to succeed in sustainable energy landscape as a potential zero emission technology, it is inevitable to reduce electricity production cost associated mainly with its MEAs, cell hardware and gas storage units. We demonstrate a diverse strategy for achieving this target with a concomitant amplification of its specific energy and power, by rolling a thin graphene oxide (GO) based MEA alone into a tubular and air breathing architecture with internal fuel storage. The unique properties of GO being a barrier for molecular fuels and proton conducting to construct a GO based cylindrical MEA. This makes the tubular PEMFC ∼75 times lighter, featuring ∼37 and ∼92 times respectively, the power and energy per overall weight, making it a potential candidate for portable applications. The intrinsic electrochemical kinetics at the three-phase boundary are somewhat affected by the bending of the MEA, albeit at overall reduction in power production cost.}, author = {Thimmappa, Ravikumar and Chattanahalli Devendrachari, Mruthyunjayachari and Shafi, Shahid and Freunberger, Stefan Alexander and Ottakam Thotiyl, Musthafa}, issn = {0360-3199}, journal = {International Journal of Hydrogen Energy}, number = {47}, pages = {22305--22315}, publisher = {Elsevier}, title = {{Proton conducting hollow graphene oxide cylinder as molecular fuel barrier for tubular H2-air fuel cell}}, doi = {10.1016/j.ijhydene.2016.08.057}, volume = {41}, year = {2016}, } @article{7294, abstract = {Mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres were prepared by non-hydrolytic sol–gel from TiCl4, VOCl3, and iPr2O at 110 °C without any solvent or additives. The samples were characterized by elemental analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, nitrogen physisorption, and impedance measurements. At low vanadium loadings, only TiO2 anatase was detected, and V2O5 scherbinaite was also detected at high vanadium loadings. The texture of the samples depended on the V loading, but all the samples appeared built of primary nanoparticles (≈10–20 nm in size) that aggregate to form mesoporous micron-sized spheres. The lithium insertion properties of these materials were evaluated by galvanostatic measurements taken using coin-type cells, in view of their application as electrode for rechargeable Li-ion batteries. The mesoporous TiO2 microspheres showed good performances, with a specific reversible capacity of 145 and 128 mAh g−1 at C/2 and C, respectively (C = 335.6 mA g−1), good coulombic efficiency, and a moderate capacity fade (6 %) from the 2nd to the 20th cycle at C/20. Although the addition of V effectively increased the electronic conductivity of the powders, the specific reversible capacity and cycling performances of the TiO2–V2O5 samples were only minimally improved for a 5 at% V loading and were lower at higher V loading.}, author = {Escamilla-Pérez, A. M. and Louvain, N. and Kaschowitz, M. and Freunberger, Stefan Alexander and Fontaine, O. and Boury, B. and Brun, N. and Mutin, P. H.}, issn = {0928-0707}, journal = {Journal of Sol-Gel Science and Technology}, number = {2}, pages = {270--278}, publisher = {Springer Nature}, title = {{Lithium insertion properties of mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres prepared by non-hydrolytic sol–gel}}, doi = {10.1007/s10971-016-4037-9}, volume = {79}, year = {2016}, } @article{7295, abstract = {Redox ionic liquids consisting of ions bearing redox moieties are receiving increasing interest in electrochemical applications, as they associate electroactive properties with the classical properties of ionic liquids. Here, biredox ionic liquid electrolytes are described in which both anion and cation are functionalized with anthraquinone and 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) groups, respectively. In-depth investigations based on crossed experimental and theoretical studies were carried out to elucidate how the bulkiness of ions bearing a redox moiety impacted electron and mass transfers, and accordingly the efficiency of electrochemical devices. The values of solvated radii of different redox ions, as well as the related kinetic constants, were extracted from cyclic voltammetry experiments. Reformulating the basic relations of electron transfer theory (based on Marcus-Hush theory) evidenced that in such redox species, with an unsymmetrical located redox centre, the electron transfer was not governed by the overall size of the solvated redox species, but rather by the radius of the redox active subunit, which takes preferential orientation towards the surface, thus allowing higher kinetic constants than what classical theory would predict. This vision opens ample opportunities for biredox ILs as electrolytes in electrochemical devices.}, author = {Mourad, Eléonore and Coustan, Laura and Freunberger, Stefan Alexander and Mehdi, Ahmad and Vioux, André and Favier, Frédérique and Fontaine, Olivier}, issn = {0013-4686}, journal = {Electrochimica Acta}, number = {7}, pages = {513--523}, publisher = {Elsevier}, title = {{Biredox ionic liquids: Electrochemical investigation and impact of ion size on electron transfer}}, doi = {10.1016/j.electacta.2016.02.211}, volume = {206}, year = {2016}, } @article{7296, abstract = {Within the scope of developing a multi-physical model describing battery behavior during and after the mechanical load (accelerations, intrusions) of a vehicle’s high voltage battery, an internal short circuit model is of deep interest for a virtual hazard assessment. The internal short resistance and the size of the affected area must be known as a minimum for determining the released heat and, in consequence, the temperatures. The internal short resistance of purpose-built dummy pouch cells, filled with electrolyte-like solvent without conductive salt, has thus been measured in a given short area under various compressive loads. The resistances for different short scenarios obtained are analyzed and described in a mathematical form. Short circuit experiments with dummy cells using an external power source have also been carried out. This set-up allows the measurement of the temperature evolution at a known current and a determination of the actual short resistance. The post-mortem analysis of the samples shows a correlation between the maximum temperatures, released short heat and the separator melt diameter.}, author = {Volck, Theo and Sinz, Wolfgang and Gstrein, Gregor and Breitfuss, Christoph and Heindl, Simon and Steffan, Hermann and Freunberger, Stefan Alexander and Wilkening, Martin and Uitz, Marlena and Fink, Clemens and Geier, Alexander}, issn = {2313-0105}, journal = {Batteries}, number = {2}, publisher = {MDPI AG}, title = {{Method for determination of the internal short resistance and heat evolution at different mechanical loads of a Lithium ion battery cell based on dummy pouch cells}}, doi = {10.3390/batteries2020008}, volume = {2}, year = {2016}, } @article{7297, abstract = {Redox mediators facilitate the oxidation of the highly insulating discharge product in metal–oxygen batteries during recharge and offer opportunities to achieve high reversible capacities. Now a design principle for selecting redox mediators that can recharge the batteries more efficiently is suggested.}, author = {Freunberger, Stefan Alexander}, issn = {2058-7546}, journal = {Nature Energy}, number = {6}, publisher = {Springer Nature}, title = {{Batteries: Charging ahead rationally}}, doi = {10.1038/nenergy.2016.74}, volume = {1}, year = {2016}, } @article{7298, abstract = {Lithium-ion batteries are in widespread use in electric vehicles and hybrid vehicles. Besides features like energy density, cost, lifetime, and recyclability the safety of a battery system is of prime importance. The separator material impacts all these properties and requires therefore an informed selection. The interplay between the mechanical and electrochemical properties as key selection criteria is investigated. Mechanical properties were investigated using tensile and puncture penetration tests at abuse relevant conditions. To investigate the electrochemical performance in terms of effective conductivity a method based on impedance spectroscopy was introduced. This methodology is applied to evaluate ten commercial separators which allows for a trade-off analysis of mechanical versus electrochemical performance. Based on the results, and in combination with other factors, this offers an effective approach to select suitable separators for automotive applications.}, author = {Plaimer, Martin and Breitfuß, Christoph and Sinz, Wolfgang and Heindl, Simon F. and Ellersdorfer, Christian and Steffan, Hermann and Wilkening, Martin and Hennige, Volker and Tatschl, Reinhard and Geier, Alexander and Schramm, Christian and Freunberger, Stefan Alexander}, issn = {0378-7753}, journal = {Journal of Power Sources}, number = {2}, pages = {702--710}, publisher = {Elsevier}, title = {{Evaluating the trade-off between mechanical and electrochemical performance of separators for lithium-ion batteries: Methodology and application}}, doi = {10.1016/j.jpowsour.2015.12.047}, volume = {306}, year = {2016}, } @article{985, abstract = {We report on magnetotransport studies of dual-gated, Bernal-stacked trilayer graphene (TLG) encapsulated in boron nitride crystals. We observe a quantum Hall effect staircase which indicates a complete lifting of the 12-fold degeneracy of the zeroth Landau level. As a function of perpendicular electric field, our data exhibit a sequence of phase transitions between all integer quantum Hall states in the filling factor interval -8<ν<0. We develop a theoretical model and argue that, in contrast to monolayer and bilayer graphene, the observed Landau level splittings and quantum Hall phase transitions can be understood within a single-particle picture, but imply the presence of a charge density imbalance between the inner and outer layers of TLG, even at charge neutrality and zero transverse electric field. Our results indicate the importance of a previously unaccounted band structure parameter which, together with a more accurate estimate of the other tight-binding parameters, results in a significantly improved determination of the electronic and Landau level structure of TLG.}, author = {Campos, Leonardo and Taychatanapat, Thiti and Serbyn, Maksym and Surakitbovorn, Kawin and Watanabe, Kenji and Taniguchi, Takashi and Abanin, Dmitry and Jarillo Herrero, Pablo}, issn = { 079-7114}, journal = {Physical Review Letters}, number = {6}, publisher = {American Physical Society}, title = {{Landau Level Splittings, Phase Transitions, and Nonuniform Charge Distribution in Trilayer Graphene}}, doi = {10.1103/PhysRevLett.117.066601}, volume = {117}, year = {2016}, } @article{986, abstract = {The many-body localization transition (MBLT) between ergodic and many-body localized phases in disordered interacting systems is a subject of much recent interest. The statistics of eigenenergies is known to be a powerful probe of crossovers between ergodic and integrable systems in simpler examples of quantum chaos. We consider the evolution of the spectral statistics across the MBLT, starting with mapping to a Brownian motion process that analytically relates the spectral properties to the statistics of matrix elements. We demonstrate that the flow from Wigner-Dyson to Poisson statistics is a two-stage process. First, a fractal enhancement of matrix elements upon approaching the MBLT from the delocalized side produces an effective power-law interaction between energy levels, and leads to a plasma model for level statistics. At the second stage, the gas of eigenvalues has local interactions and the level statistics belongs to a semi-Poisson universality class. We verify our findings numerically on the XXZ spin chain. We provide a microscopic understanding of the level statistics across the MBLT and discuss implications for the transition that are strong constraints on possible theories.}, author = {Serbyn, Maksym and Moore, Joel}, issn = {2469-9969}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {4}, publisher = {American Physical Society}, title = {{Spectral statistics across the many-body localization transition}}, doi = {10.1103/PhysRevB.93.041424}, volume = {93}, year = {2016}, } @misc{9862, author = {Roux, Camille and Fraisse, Christelle and Romiguier, Jonathan and Anciaux, Youann and Galtier, Nicolas and Bierne, Nicolas}, publisher = {Public Library of Science}, title = {{Simulation study to test the robustness of ABC in face of recent times of divergence}}, doi = {10.1371/journal.pbio.2000234.s016}, year = {2016}, } @misc{9863, author = {Roux, Camille and Fraisse, Christelle and Romiguier, Jonathan and Anciaux, Youann and Galtier, Nicolas and Bierne, Nicolas}, publisher = {Public Library of Science}, title = {{Accessions of surveyed individuals, geographic locations and summary statistics}}, doi = {10.1371/journal.pbio.2000234.s017}, year = {2016}, } @misc{9864, abstract = {Viral capsids are structurally constrained by interactions among the amino acids (AAs) of their constituent proteins. Therefore, epistasis is expected to evolve among physically interacting sites and to influence the rates of substitution. To study the evolution of epistasis, we focused on the major structural protein of the ϕX174 phage family by, first, reconstructing the ancestral protein sequences of 18 species using a Bayesian statistical framework. The inferred ancestral reconstruction differed at eight AAs, for a total of 256 possible ancestral haplotypes. For each ancestral haplotype and the extant species, we estimated, in silico, the distribution of free energies and epistasis of the capsid structure. We found that free energy has not significantly increased but epistasis has. We decomposed epistasis up to fifth order and found that higher-order epistasis sometimes compensates pairwise interactions making the free energy seem additive. The dN/dS ratio is low, suggesting strong purifying selection, and that structure is under stabilizing selection. We synthesized phages carrying ancestral haplotypes of the coat protein gene and measured their fitness experimentally. Our findings indicate that stabilizing mutations can have higher fitness, and that fitness optima do not necessarily coincide with energy minima.}, author = {Fernandes Redondo, Rodrigo A and de Vladar, Harold and Włodarski, Tomasz and Bollback, Jonathan P}, publisher = {The Royal Society}, title = {{Data from evolutionary interplay between structure, energy and epistasis in the coat protein of the ϕX174 phage family}}, doi = {10.6084/m9.figshare.4315652.v1}, year = {2016}, } @misc{9866, author = {Zagórski, Marcin P and Burda, Zdzisław and Wacław, Bartłomiej}, publisher = {Public Library of Science}, title = {{ZIP-archived directory containing all data and computer programs}}, doi = {10.1371/journal.pcbi.1005218.s009}, year = {2016}, } @misc{9867, abstract = {In the beginning of our experiment, subjects were asked to read a few pages on their computer screens that would explain the rules of the subsequent game. Here, we provide these instructions, translated from German.}, author = {Hilbe, Christian and Hagel, Kristin and Milinski, Manfred}, publisher = {Public Library of Science}, title = {{Experimental game instructions}}, doi = {10.1371/journal.pone.0163867.s008}, year = {2016}, } @misc{9868, abstract = {The raw data file containing the experimental decisions of all our study subjects.}, author = {Hilbe, Christian and Hagel, Kristin and Milinski, Manfred}, publisher = {Public Library of Science}, title = {{Experimental data}}, doi = {10.1371/journal.pone.0163867.s009}, year = {2016}, } @misc{9869, abstract = {A lower bound on the error of a positional estimator with limited positional information is derived.}, author = {Hillenbrand, Patrick and Gerland, Ulrich and Tkačik, Gašper}, publisher = {Public Library of Science}, title = {{Error bound on an estimator of position}}, doi = {10.1371/journal.pone.0163628.s001}, year = {2016}, } @article{987, abstract = {In contrast to bulk FeSe, which exhibits nematic order and low temperature superconductivity, highly doped FeSe reverses the situation, having high temperature superconductivity appearing alongside a suppression of nematic order. To investigate this phenomenon, we study a minimal electronic model of FeSe, with interactions that enhance nematic fluctuations. This model is sign problem free, and is simulated using determinant quantum Monte Carlo (DQMC). We developed a DQMC algorithm with parallel tempering, which proves to be an efficient source of global updates and allows us to access the region of strong interactions. Over a wide range of intermediate couplings, we observe superconductivity with an extended s-wave order parameter, along with enhanced, but short-ranged, q=(0,0) ferro-orbital (nematic) order. These results are consistent with approximate weak-coupling treatments that predict that nematic fluctuations lead to superconducting pairing. Surprisingly, in the parameter range under study, we do not observe nematic long-range order. Instead, at stronger coupling an unusual insulating phase with q=(π,π) antiferro-orbital order appears, which is missed by weak-coupling approximations.}, author = {Dumitrescu, Philipp and Serbyn, Maksym and Scalettar, Richard and Vishwanath, Ashvin}, issn = {2469-9969}, journal = {Physical Review B}, number = {15}, publisher = {American Physical Society}, title = {{Superconductivity and nematic fluctuations in a model of doped FeSe monolayers: Determinant quantum Monte Carlo study}}, doi = {10.1103/PhysRevB.94.155127}, volume = {94}, year = {2016}, } @misc{9870, abstract = {The effect of noise in the input field on an Ising model is approximated. Furthermore, methods to compute positional information in an Ising model by transfer matrices and Monte Carlo sampling are outlined.}, author = {Hillenbrand, Patrick and Gerland, Ulrich and Tkačik, Gašper}, publisher = {Public Library of Science}, title = {{Computation of positional information in an Ising model}}, doi = {10.1371/journal.pone.0163628.s002}, year = {2016}, } @misc{9871, abstract = {The positional information in a discrete morphogen field with Gaussian noise is computed.}, author = {Hillenbrand, Patrick and Gerland, Ulrich and Tkačik, Gašper}, publisher = {Public Library of Science}, title = {{Computation of positional information in a discrete morphogen field}}, doi = {10.1371/journal.pone.0163628.s003}, year = {2016}, } @misc{9873, author = {Boehm, Alex and Arnoldini, Markus and Bergmiller, Tobias and Röösli, Thomas and Bigosch, Colette and Ackermann, Martin}, publisher = {Public Library of Science}, title = {{Quantification of the growth rate reduction as a consequence of age-specific mortality}}, doi = {10.1371/journal.pgen.1005974.s015}, year = {2016}, } @article{363, abstract = {Lead halide perovskite materials have attracted significant attention in the context of photovoltaics and other optoelectronic applications, and recently, research efforts have been directed to nanostructured lead halide perovskites. Collodial nanocrystals (NCs) of cesium lead halides (CsPbX3, X = Cl, Br, I) exhibit bright photoluminescence, with emission tunable over the entire visible spectral region. However, previous studies on CsPbX3 NCs did not address key aspects of their chemistry and photophysics such as surface chemistry and quantitative light absorption. Here, we elaborate on the synthesis of CsPbBr3 NCs and their surface chemistry. In addition, the intrinsic absorption coefficient was determined experimentally by combining elemental analysis with accurate optical absorption measurements. 1H solution nuclear magnetic resonance spectroscopy was used to characterize sample purity, elucidate the surface chemistry, and evaluate the influence of purification methods on the surface composition. We find that ligand binding to the NC surface is highly dynamic, and therefore, ligands are easily lost during the isolation and purification procedures. However, when a small amount of both oleic acid and oleylamine is added, the NCs can be purified, maintaining optical, colloidal, and material integrity. In addition, we find that a high amine content in the ligand shell increases the quantum yield due to the improved binding of the carboxylic acid.}, author = {De Roo, Jonathan and Ibáñez, Maria and Geiregat, Pieter and Nedelcu, Georgian and Walravens, Willem and Maes, Jorick and Martins, Jose and Van Driessche, Isabel and Kovalenko, Maksym and Hens, Zeger}, issn = {1936-086X}, journal = {Nano}, keywords = {NMR, CsPbBr3, absorption coefficient, surface chemistry}, number = {2}, pages = {2071 -- 2081}, publisher = {American Chemical Society}, title = {{Highly dynamic ligand binding and light absorption coefficient of cesium lead bromide perovskite nanocrystals}}, doi = {10.1021/acsnano.5b06295}, volume = {10}, year = {2016}, }