bluuebunny/crossref_metadata_2025_split huggingface dataset:
PBI-Based Membranes for High Temperature Pemfcs: Proton Transport and Functional Properties
Authors: Mustarelli Piercarlo 
Published: February 2020

High-temperature (100-200C, HT) PEMFCs are attracting for their applications in automotive. The development of devices operating in this temperature range likely requires the substitution of NafionTM with other polymers which are chemically and electrochemically stable, and can offer the required proton conductivity level (>10-2 ohm-1 cm-1) under low humidity conditions.
Polybenzimidazole and its derivatives are good candidates to work as the electrolyte in HT-PEMFCs. In the last years we developed several PBI-based membranes, including moieties with more nitrogen atoms in the main chain (1, 2), with ether oxygens (3), sulphonic groups (4), fluorine atoms and also (nano)composites (5-8). In this paper, we report on the functional properties of this class of electrolytes, and discuss the proton transport mechanisms at different doping conditions.

Carollo, E. Quartarone, C. Tomasi, P. Mustarelli, F. Belotti, A. Magistris, L. Garlaschelli and P.P. Righetti, J. Power Sources, 160 (2006) 175-180.

E. Quartarone, A. Magistris, P. Mustarelli, S. Grandi, A. Carollo, G.Z. Żukowska, J.E. Garbarczyk, J.L. Nowiński, C. Gerbaldi, S. Bodoardo, Fuel Cells 9 (2009) 349-355.

S. Angioni, P.P. Righetti, E. Quartarone, E. Dilena, P. Mustarelli, A. Magistris, International Journal of Hydrogen Energy, 36 (2011) 7174-7182.

S. Angioni, D. C. Villa, S. Dal Barco, E. Quartarone, P. P. Righetti, P. Mustarelli, J. Mater. Chem. A, accepted. DOI: 10.1039/C3TA12200J

P. Mustarelli, E. Quartarone, S. Grandi, A. Carollo and A. Magistris, Advanced Materials 20 (2008), 1339-1343.

E. Quartarone, P. Mustarelli, A. Carollo, S. Grandi, A. Magistris, C. Gerbaldi, Fuel Cells 9 (2009) 231-236.

V. Kurdakova, E. Quartarone, P. Mustarelli, A. Magistris, E. Caponetti, M.L. Saladino, Journal of Power Sources, 195 (2010) 7765-7769.

V. Di Noto, M. Piga, G.A. Giffin, E. Quartarone, P.P. Righetti, P. Mustarelli, A. Magistris, Physical Chemistry Chemical Physics, 13 (2011) 12146-12154.
Redox-Gated Molecular Memory Devices Based on Dynamic Doping of Polythiophene
Authors: McCreery Richard Louis , Das Bikas , Pillai Rajesh , Pekas Nikola , James David B 
Published: February 2020

A solid state electrochemical cell resembling a field effect transistor will be described which can act as a nonvolatile memory element. “Write” and “Erase” pulses cause oxidation of a polythiophene to its conducting form, while the conductance is monitored by a “read” circuit. Raman and UV-Vis spectroelectrochemistry were used during device operation to investigate redox reactions which underlie memory operation. Important electrochemical concepts which control device operation include activated electron transfer, ion motion, and extended conjugation. In particular, internal ion transport creates ohmic potential losses which slow W/E operation, but can be significantly improved with higher mobility solid electrolytes. Applications seeking to augment existing silicon electronics with molecular components will be described.
Recent references:
(1) Yan, H.; Bergren, A. J.; McCreery, R.; Della Rocca, M. L.; Martin, P.; Lafarge, P.; Lacroix, J. C.; Activationless charge transport across 4.5 to 22 nm in molecular electronic junctions; Proceedings of the National Academy of Sciences
2013, 110, 5326.
(2) McCreery, R.; Yan, H.; Bergren, A. J.; A Critical Perspective on Molecular Electronic Junctions: There is Plenty of Room in the Middle; Phys. Chem. Chem. Phys.
2013, 15, 1065.
(3) Sayed, S. Y.; Fereiro, J. A.; Yan, H.; McCreery, R. L.; Bergren, A. J.; Charge transport in molecular electronic junctions: Compression of the molecular tunnel barrier in the strong coupling regime; Proceedings of the National Academy of Sciences
2012, 109, 11498.
(4) Kumar, R.; Pillai, R. G.; Pekas, N.; Wu, Y.; McCreery, R. L.; Spatially Resolved Raman Spectroelectrochemistry of Solid-State Polythiophene/Viologen Memory Devices; Journal of the American Chemical Society
2012, 134, 14869.
Characterisation of Novel Organic Sodium Salts
Authors: Bitner Anna , Niedzicki Leszek , Plewa-Marczewska Anna , Marcinek Marek , Dranka Maciej , Zukowska Grazyna Zofia , Wieczorek Wladyslaw 
Published: February 2020

Growing application of Li-ion and Li-polymer batteries for hybrid electric cars, electric vehicles, mobile devices etc. requires a large amount of lithium in the form of Li2CO3 every year. High price and relatively small world reserves of 13 million tons, forced to look for new materials possible to use in battery technology.
That is a clear reason for research effort to find out new types well performed batteries of high energy density, low cost, increased safety and tolerated by the environment. The logical way is to look for lithium analogues with similar chemistry properties and higher resources on the planet (sixth most abundant element and the most abundant alkali metal on Earth).
Sodium has molar mass and only slightly lower than lithium red-ox potential (2.73V). Low cost (about 7 times lower than lithium) and enormously easier and almost unlimited worldwide reserves makes him a really promising candidate. Metallic sodium does not form dendrites being a key issue if lithium metallic anodes (with gigantic theoretical capacity of 1190 mAh·g-1) were tested in present batteries. Several secondary advantages only promotes sodium concept for ex. cheaper than aluminum current collectors might be applied
Novel sodium salts, with five-membered ring imidazolium anion, were synthesized. Salts were found extremely stable up to more than 300oC (TGA). Moreover interesting properties of synthesized salts and their solutions in the PC solvent were proven by structural characteristic, electrochemical testing and Raman spectroscopy. NaTDI and NaPDI based electrolytes in PC show good conductivity with the values about 4mScm-1 at 20oC for salt concentration 0.5M and 1M for both salts. Ionic conductivities collected for both salts are almost the same considering slope over temperatures and pure values. Interestingly the high values of the conductivities are reached for 0.5M salt concentrations which is extreme advantage if we consider material savings. Superior properties were also confirmed by Raman spectroscopy used for the ionic association monitoring. Raman spectroscopy showed excellent salts dissociation in carbonate as PC and absence of ion-pairs for concentration up to 0.5M. A long distance framework type ordering of both TDI- and PDI- anions were also observed via extensive X-ray studies (data not presented here). According to previous computional simulations such a superfine structures are suspect to play the crucial role of sodium coordination and by that facilitating substantially cation transport properties. Combining this with thermal stability over 300oC plus the elevated electrochemical stability over 4.5V for NaTDIand 4.2V NaPDI vs Na/Na+ makes these salts interesting as acandidate for electrolyte’s sodium salt carrier.
Phosphorus-Doped Carbon as Efficient Electrocatalysts for Oxygen Reduction Reaction
Authors: Yang Zhenrong , Wu Jiao , Gong Xin , Strasser Peter , Yang Ruizhi 
Published: February 2020

Electrocatalytic oxygen reduction reaction (ORR) has attracted much attention due to its importance in fuel cells and metal–air batteries [1-3]. The ORR in fuel cells and metal-air batteries require catalysts to accelerate the reaction rate owing to its sluggish kinetics and complicated reaction mechanism. Pt-based ca talysts are known to be the most active catalysts. However, Pt is scarce and expensive. The development of low-cost and efficient catalysts for the ORR is highly desirable [4,5]. Heteroatoms-doped carbon meterials have been explored as alternative electrocatalysts for the ORR due to their more abundance, lower price and high activity [6,7].
In this work, phosphorus (P)-doped carbon is facilely synthesized by both ex-situ and in-situ doping method. The catalytic activity of P-doped carbon for the ORR in 0.1 M KOH solution has been studied by using a rotating ring-disk electrode (RRDE) technique. The RRDE results show that P-doped carbon exhibits excellent catalytic activity for the ORR (Fig.1 and Fig.2)and long-term stability in basic media (Fig.3 ). The high elecctrocatalytic activity and durability of P-doped carbon are primarily attributed to the P-doping in the carbon lattice. Moreover, the factors that influence the ORR activity of P-doped microporous carbon are studied in detail. This kind of low cost, highly active and sustainable P-doped carbon xerogels could be used as a potential electrocatalyst for the cathodic ORR in fuel cells and metal-air batteries.
Acknowledgements
This work is supported by National Natural Science Foundation of China (Nos. 51272167 and 21206101 ), Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (12KJB430010) and Sino-German Network on Electromobility.
References
[1] P. G. Bruce, L. J. Hardwick, K. M. Abraham, Mater. Res. Soc.Bull. 36,506 (2011).
[2] M. Armand, J. M. Tarascon, Nature 451,652 (2008) .
[3] V. Neburchilov, H. J. Wang, J. J. Martin & W. Qu, J. Power Sources 195,1271 (2010).
[4] P.H. Matter, U.S. Ozkan, Catal. Lett. 109, 115(2006).
[5] T.Fujigaya , M.Okamoto, N.Nakashima , Carbon 47, 3227(2009).
[6] J.-S.Lee, G.S. Park, S. T. Kim, M.L. Liu and J.Cho, Angew. Chem. Int. Ed. 51, 1 (2012).
[7] N.S.Stephanie, A. Wieckowski, J.Electroanal. Chem. 652, 44 (2011).
Figure 1. Linear sweeping voltammograms (LSVs) on rotating ring-disk electrode (RRDE) for carbon and P-doped carbon with different amount of P. The disk potential was scanned at 10 mV s-1 and the ring potential was fixed at 0.5 V.
Figure 2. Tafel plots of carbon, P-doped carbon and commercial Pt/C (20 wt.% Pt on carbon) derived by the masstransport correction of corresponding LSV data recorded in O2-saturated 0.1 M KOH.
Figure 3. LSVs of P-doped carbon and of commercial Pt/C (20 wt.% Pt on carbon) for the 1st cycle and 2000 th cycle in O2-saturated 0.1 M KOH at a rotating speed of 1600 rpm.
In Operando Neutron Reflectometry Measurements Demonstrate Structural Stability in Thin Film Silicon Anodes for Lithium Ion Batteries
Authors: DeCaluwe Steven C , Dhar Bal-Mukund , Dura Joseph , Wang Howard 
Published: February 2020

Despite its incredibly high theoretical capacity (~4200 mA-h/g), implementation of Si electrodes as high-capacity Li-battery anodes is hindered by poor mechanical durability. Si lithiation is accompanied by very high mechanical strain values, with nearly 370% volume expansion at maximum capacity, which typically leads to fracture and pulverization of the material and eventual battery failure. While numerous strategies have been employed to improve the durability of Si anodes, including nano-structured anode architectures, composite anode materials, and protective coatings, efforts have yet to identify a Si anode design that is mechanically robust and maintains a stable anode capacity. At least part of the difficulty is due to a lack of fundamental insight into the correlation between structure, mechanical properties, and function for Si anodes, owing to a paucity of in situ techniques to definitively observe them.
In this presentation, we report the structural and composition changes in an amorphous thin-film silicon anode with a protective Al sub-oxide (AlOx) capping layer, using in operando neutron reflectivity (NR) and electronic impedance spectroscopy (EIS) measurements. NR measurements were carried out in situ on an operating Li half-cell at various charge states over six shallow charge-discharge cycles. These measurements quantify the correlation between mesoscopic strain and the degree of lithiation in a 10-nm thick amorphous silicon thin-film anode, which expands and contracts with repeated cycling (Figure 1).
Results demonstrate the mechanical durability of both the Si thin-film anode and the protective AlOx layer, which maintain their low surface roughness and film integrity over the course of the measurements. While the macroscopic strain of the Si shows significant non-linearity with Li content after several shallow charge-discharge cycles, in agreement with previous reports1, careful inclusion of a-Si microstructural effects (via direct measurement of the a-Si porosity) reveal that the volumetric strain for the solid portion of a-Si thin films varies linearly with lithium content (Figure 2). Results demonstrate that the porosity is eliminated during the expansion that accompanies lithiation, and is then recovered during subsequent de-lithiation. Furthermore, it is shown here that the delithiated a-Si porosity does not vary significantly over the course of the measurements – ranging from 10.0 [5.4 – 28.0]% in the as-deposited state to 13.1 [10.02 – 15.73]% after 6 shallow charge and discharge cycles – demonstrating the structural reproducibility of the thin-film anode.
References:
1. Chevrier, V. L. and Dahn, J. R., J. Electrochem. Soc.
2009,
156 (6), A454-A458.
Numerical Simulation of Electrolyte-Supported Planar Button Solid Oxide Fuel Cells with Layered Electrolytes
Authors: Aman Amjad , Gentile Russell , Chen Yan , Lugovy Mykola , Xu Yunjun , Huang Xinyu , Orlovskaya Nina 
Published: February 2020

Multi-layered (Y2O3)0.08(ZrO2)0.92 / (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (YSZ/SCSZ) electrolytes were designed for intermediate temperature Solid Oxide Fuel Cells (SOFCs), so that the inner SCSZ layers provided superior ionic conductivity and the outer YSZ layers provided chemical and phase stability. A total of nine electrolyte designs were developed and tested. Due to the mismatch in the thermal expansion coefficients between the two electrolyte materials, residual stresses develop between the layers. It was noticed that the ionic conductivity of the electrolytes is enhanced due to the presence of residual stresses. To study the electrochemical performance of the SOFC with different electrolyte materials and configurations, an electrolyte-supported planar button SOFC is modeled using COMSOL Multiphysics® 4.3. The main governing equations include the charge conservation equation, Maxwell-Stefan diffusion model, Butler-Volmer equation, and Brinkman equation. The cathode and anode materials used are (La0.6Sr0.4)0.95-0.99Co0.2Fe0.8O3 and Ni-YSZ respectively. Validation of the model was done against experimental results of another planar SOFC by Joongmyeon et al. (Journal of Power Sources, 2007). The simulations show that SOFCs with 3-layered pure SCSZ electrolyte produced the highest power density while the single cell with 6-layered pure YSZ electrolyte produced the least power density. These results make sense, since the increase in the electrolyte thickness increases the ohmic losses. The model developed can be used in further studying the behavior of the cells.
In order to study the mechanical properties of the electrolytes, biaxial flexure tests were performed via a ring-on-ring method at room temperature and 800 °C. Due to the high deflection of the electrolytes, a non-linear dependence between stress and load was observed. Therefore, the geometric non-linearity feature was utilized in the modeling to calculate the maximum tensile stress in the specimen at a given load. Results showed that layered electrolytes have higher biaxial flexure strength. This is theorized to be due to the presence of compressive stresses at the outer YSZ layers. Weibull statistics was used on stress calculations to verify the results.
Invited Presentation: Effect of Elastic Strain and Dislocations on Oxide Ion Diffusion and Oxygen Exchange Kinetics on Oxides
Authors: Yildiz Bilge 
Published: February 2020

How can the oxygen non-stoichiometry, oxygen diffusion and oxygen reduction kinetics be altered in functional oxides by lattice strain? This question has recently attracted wide interest for enabling a new route for attaining fast oxygen exchange and transport kinetics, and obtaining fundamental answers to this question is important for a range of technologies including high performance solid oxide fuel cells, oxide based sensors, separation membranes and memristors. By applying mechanical stress, the inherent energy landscape of the reactions involved on the material can be altered. For example, in theory one can turn an endothermic reaction into an exothermic one, and reduce the energy barriers by applying lattice strain. This is the so-called mechano-chemical coupling, and when applied on electrochemical systems we can introduce the term mechano-electro-chemistry.
In this talk, we will discuss recent work that probes quantitatively the mechanisms by which elastic strain impacts surface reactivity and diffusion kinetics in fluorite and perovskite oxides. Computationally, using ab initio and atomistic simulations, we discovered that lattice strain can accelerate the ionic transport in 8%Y2O3-ZrO2 by reducing the ion migration energy barriers. Combining surface chemical characterization on model thin films with ab initio modeling, we demonstrated for the first time that tensile lattice strain favors oxygen exchange kinetics on both the oxygen-deficient (La,Sr)CoO3-d and (La,Sr)MnO3-d and the oxygen-excess Nd2NiO4+d by impacting the energies of oxygen adsorption and dissociation, oxygen vacancy formation, oxygen diffusion, cation segregation and the electron transfer process. The favorable impact of tensile lattice strain on these elementary reactions was validated at the collective level by quantifying the oxygen surface exchange and diffusion kinetics with isotope exchange measurements on (La,Sr)CoO3-d. Lastly, we will discuss the impact of dislocations in ionic crystals, as doped CeO2 and ZrO2 on the distribution of charged defects and mobility of oxygen vacancies. These results together put forth both elastic strain and the dislocations to be important factors that impressively changes the kinetics of charge transport and reactivity in functional oxides.
Highly Diastereoselective Cyclopropanation of Olefins Catalysed By a C2-Symmetrical Chiral Iron Porphyrin Complex
Authors: Gallo Emma , Intrieri Daniela , Le Gac Stéphane , Caselli Alessandro , Rose Eric , Boitrel Bernard 
Published: February 2020

Compounds containing cyclopropane units play a crucial role in both synthetic and pharmaceutical chemistry due to high reactivity and biological properties of the three-membered ring.[1] Consequently, the interest of the research community in developing new methodologies to synthesise cyclopropanes is strongly increasing. Amongst the synthetic procedures available, the one-pot reaction of diazo compounds with olefins is a sustainable and atom-efficient strategy due to the formation of N2as the only stoichiometric by product.
Catalytic enantio- and diasteroselective olefin cyclopropanations [2] have been extensively explored and metal porphyrin complexes represent a very active and stereoselective class of catalysts. Some years ago we reported on the catalytic efficiency of chiral cobalt(II)-binaphthyl porphyrins in asymmetric cyclopropanations, [3] and recorded positive data encouraging us to synthesise the structurally related chiral porphyrin 1 and its iron(III) complex 2 (see figure). The catalytic activity of 2 in the asymmetric cyclopropanation of olefins by diazo compounds was investigated. Cyclopropanes were obtained with excellent yields (up to 99%), enantio- and diasteroselectivities (eetrans
up to 80%, cis/trans ratios up to 99%). In addition to that, outstanding values of TON and TOF (20,000 and 120,000/h respectively) were achieved. [4]

References

[1] A. K. Kumar, Intern. J. Pharm. and Pharm. Sci.
2013,
5, 467-472.
[2] D. Intrieri, A. Caselli and E. Gallo, Eur. J. Inorg. Chem.
2011, 5071-5081.
[3] (a) S. Fantauzzi, E. Gallo, E. Rose, N. Raoul, A. Caselli, S. Issa, F. Ragaini and S. Cenini, Organometallics, 2008, 27, 6143-6151. (b) A. Penoni, R. Wanke, S. Tollari, E. Gallo, D. Musella, F. Ragaini, F. Demartin and S. Cenini, Eur. J. Inorg. Chem.
2003, 1452-1460.
[4] D. Intrieri, S. Le Gac, A. Caselli, E. Rose, B. Boitrel and E. Gallo submitted
Single Molecule Force Spectroscopy (Invited)
Authors: Meyer Ernst , Pawlak Remy , Glatzel Thilo , Kawai Shigeki , Baratoff Alexis 
Published: February 2020

Recently, intramolecular resolution is studied on a variety of molecules. A further challenge is the manipulation of molecules on surfaces, including the controlled rotation, which means that the direction of rotation of the molecule can be chosen by the experimentalist [1]. The control of the probing tip is of central importance for a quantitative understanding of nc-AFM imaging and force spectroscopy. Progress has been made by a variety of preparation procedures: sputtering, indentation or pick-up of molecules, such as CO. The attachement of a single molecule to the end of the tip is shown for the case of a functionalized porphyrin, which can used as a stable probing tip for imaging in the attractive as well as the repulsive regime.
[1] R. Pawlak, S. Fremy, S. Kawai, T. Glatzel, H. Fang, L.-A. Fendt, F. Diederich, and E. Meyer , Directed rotations of single porphyrin molecules controlled by localized force spectroscopy, ACS Nano, 6, (2012), 6318–6324
(Invited) Frequency Dispersion and Band Alignments in ZrO2/n-GaAs MOS Capacitor
Authors: Konda R B , White C , Thomas D , Yang Q , Sahu D , Pradhan Aswini K 
Published: February 2020

Compound III-V semiconductors such as GaAs have the potential to replace Si as the channel material in metal-oxide-semiconductor-field-effect-transistors (MOSFET) due to their high electron mobility. However, it is extremely important to remove native oxide from the surface of GaAs. GaAs surfaces were self-cleaned through fast pulsing of the Trimethylaluminum (TMA) precursor by reducing and restraining the regrowth of native oxides using the atomic layer deposition (ALD). The thermal conversion of As-O in to Ga-O reduction was evaluated by the x-ray photoelectron spectroscopy. Metal oxide semiconductor (MOS) capacitor was using ZrO2 as high-k gate dielectric on n-GaAs substrates, and their superior performance in electrical properties has been demonstrated. ZrO2/GaAs capacitor exhibits superior capacitance-voltage characteristics reduced leakage current due to reduced interfacial trap density. These studies have remarkable significance for the development of high-throughput innovative electronics, using ZrO2 as high-k dielectric.
The interfacial characteristics and band alignments of high-k ZrO2 on n-GaAs have been investigated by experimentally and density functional theory. We have demonstrated that the frequency dispersion due to interface traps in capacitance-voltage characteristics of ZrO2/GaAs interface was significantly reduced through self-cleaning by trimethylalumina. The experimental valence band offset of 2.10 eV from X-ray photoelectron spectroscopy is found to be lower than that of the calculated value of 3.02 eV. The calculated conduction band offset is 1.21 eV compared to the experimental value of 1.38 eV confirms significant reduction of interface traps due to the Fermi-level pinning minimizing band misalignment.