bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal Hydride–Oxide Paired Anode for All-Solid Li-Ion Batteries
Authors: El kharbachi Abdel , Uesato Hiroki , Yamaguchi Shotaro , Sørby Magnus Helgerud , Miyaoka Hiroki , Ichikawa Takayuki , Fjellvåg Helmer , Hauback Bjørn Christian 
Published: February 2020

A few years ago, magnesium hydride has been demonstrated to be a candidate for conversion-type anode for Li-ion batteries [1]. In fact, this material features high theoretical capacity 2037 mAh.g-1, compared to graphite-anode, and low charge-discharge polarization [1]. However, the reversible capacity is still a challenge owing to the poor conductivity of the involved entities (MgH2/LiH), along with compatibility issues with carbonate-based liquid electrolytes. By considering safety factor and environment, LiBH4 solid electrolyte has been demonstrated to be suitable for the development of all-solid Li-ion batteries based on MgH2 anode [2], in which the enhanced mobility of the Li+ ions and H– exchange effects play a key role during the electrochemical cycling. On the other hand, CoO has been reported to undergo a conversion reaction as negative electrode, but the high working potential and large cycling hysteresis hinders its quick application in Li-ion batteries [3]. Accordingly, the present work aims the study of the effect of an electrochemically “active” oxide such as CoO on the cycling performance of MgH2 anode (molar ratio 1:3), a mixture having a theoretical capacity around 1376 mAh.g-1. The final goal is to reach higher cycling performances by facing the electrical conductivity issue of metal hydrides and inhibit the formation of Li–Mg alloys in the presence of an oxide with large voltage window. Discharge-charge galvanostatic profiles were demonstrated for the 75MgH2·25CoO paired anode in which two reversible plateaus can be distinguished using LiBH4as solid electrolyte at 120°C, the later being above its phase transition with higher ionic conductivities. The prepared and optimized active materials were characterized using X-ray diffraction and photoelectron spectroscopy (XPS) before and after the electrochemical tests in a half-cell. The mechanistic properties of the hydride–oxide paired anode are presented as function of the milling time, composition and cyclability performance.

Acknowledgements

This work is financially supported by Research Council of Norway under the program EnergiX, Project no. 244054, LiMBAT - "Metal hydrides for Li-ion battery anodes".

References

[1] Y. Oumellal, A. Rougier, G.A. Nazri, J.M. Tarascon, L. Aymard, Metal hydrides for lithium-ion batteries, Nat Mater, 7 (2008) 916-921.
[2] L. Zeng, K. Kawahito, S. Ikeda, T. Ichikawa, H. Miyaoka, Y. Kojima, Metal hydride-based materials towards high performance negative electrodes for all-solid-state lithium-ion batteries, Chem. Commun., 51 (2015) 9773-9776.
[3] P. Poizot, S. Laruelle, S. Grugeon, L. Dupont, J.M. Tarascon, Nano-sized transition-metal oxides as negative-electrode materials for lithium-ion batteries, Nature, 407 (2000) 496-499.
Engineered Porous Foam Electrodes - New Approaches to Dendrite-Free Anodes for Li-Metal Batteries
Authors: Jampani Hanumantha Prashanth , Day Brian Austin , Datta Moni Kanchan , Murugavel Shanthi Pavithra , Gattu Bharat , Kumta Prashant N 
Published: February 2020

Dendrite formation is a well-known metallurgical phenomenon occurring as a result of several energy minimization processes including preferential growth during solidification or stress-related grain-boundary evolution(1, 2). The occurrence of dendritic structures in electrochemical cells however, occurs as a result of electrochemical stripping/plating steps involving nucleation and growth processes(3).
In this work, engineered porous foams are demonstrated as stable electrodes with high coulombic efficiency and limited orthogonal growth of surface dendrites. This unique approach is used to address dendritic growth and volumetric changes associated with plating/deplating of large volumetric amounts of lithium to generate thick lithium metal anodes. Figure 1 depicts the foam morphology as well as displays the superior performance of the new engineered electrodes over 100 cycles where almost no drop in coulombic efficiency is observed at very high current densities of ~100 mA/cm2. This presentation will examine the mechanisms associated with fabrication and design of such engineered porous foam electrodes resulting in the depicted noteworthy stable cycling.

Figure caption:

Figure 1: (a) SEM image of porous foam electrodes (b) Lithium symmetric cell using commercial lithium foils showing the rapid drop in charge-discharge capacity; (c) New engineered lithium electrodes showing excellent coulombic efficiency.

References

1. S.-C. Huang and M. Glicksman, Acta Metallurgica, 29, 701 (1981).
2. T. Okamoto and K. Kishitake, Journal of Crystal Growth, 29, 137 (1975).
3. A. Despic, J. Diggle and J. M. Bockris, Journal of The Electrochemical Society, 115, 507 (1968).

Figure 1
Orientation Effects of Electrode with Various Wettability on Deep Discharge Capacity of Li-O2 Batteries
Authors: Wang Fangzhou , Li Xianglin 
Published: February 2020

The low oxygen diffusion rate in electrolyte causes great capacity loss in Li-O2 batteries. It is desirable to adjust the wettability of electrode such that more gas phase channels can contribution to increasing the discharge capacity. Lyophobic (or lyophilic) electrodes were fabricated by mixing binders such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) with Acetylene Black carbon particles. Customized electrodes were madd by coating the mixture on one side of a piece of untreated carbon cloth (210 µm thick) until the carbon loading reached about 2mg/cm2. 1 mol/L bis(trifluoromethane)sulfonimide lithium salt (LiTFSI) dissolved in tetraethylene glycol dimethyl ether (TEGDME) was utilized to characterize the surface wettability of customized electrodes by contact angle measurement. The contact angle between the coated surface of electrode with 15% PTFE and electrolyte (5µL) was 128.8o while it was 36.5o (unstable) for electrode with 15% PVDF. Discharge capacities of the customized electrodes in Li-O2 batteries were first measured with coated layers facing the lithium metal. Discharge capacities with 2V cut-off voltage were 4160.8 mAh/g (15% PTFE) and 1665.8 mAh/g (15% PVDF) at 0.1 mA/cm2, respectively. Then, discharge capacities of the customized electrodes were measured with the coated layer facing the oxygen channel. The discharge capacity of electrode with 15% PVDF increased to 2778.8 mAh/g while that of electrode with 15% PTFE decreased to 3401.8 mAh/g. Concerning the electrode with PVDF 15%, more deep discharge capacity was obtained when the coated layer was placed facing O2 due to the fact that more reaction sites were created in the lyophilic electrode and the O2 diffusion path to reaction sites (in the coated layer) was shorter in this configuration. The opposite trend observed with the electrode with PTFE 15% may be attributed to the fact that lyophobic coated layer repelled electrolyte and decreased the number of reaction sites. Under the same discharge current rate, the electrode was blocked by the generated solid Li2O2 more quickly as the reaction continued.
Long-Life Air Electrode for Rechargeable Zinc-Air Batteries
Authors: Lee Yi-Cheng , Jung Shiauh-Ping , Ho Shu-Mei , Lee Chun-I , Hsueh Kan-Lin , Wu Ching-Chen , Yang Chang-Chung 
Published: February 2020

Energy storage technology is attracting more attention with world-wide increase of renewable energy deployment, such as solar and wind power. With energy storage, electrical energy from photovoltaic cells or wind turbines can be stored when production exceeds consumption and back to the grid when load is demanded. The energy storage devices can also serve as a part of distributed power generation system for remote islands or uninterruptible power supply applications. Usually the system is installed in rural areas and even subjected to harsh temperatures and punishing humidity. Therefore, reliable and efficient energy storage is required. However, most existing mature energy storage technologies, such as Ni-Cd, Ni-MH and Li-ion, can barely satisfy both issues of safety and low cost. Metal air batteries have high theoretical specific energy density, being capable of fulfilling multiple needs for the next generation of mobile/stationary energy storage system. They are also environmentally benign, and inexpensive; frequently used metal anodes including Al, Zn, and Fe are naturally abundant. However, an air electrode with the capability of possessing both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) efficiently is still not well developed at the moment. In the present work, the bifunctional air electrode composed of alpha phase of manganese oxides or silver particles, as ORR catalysts, grown on the surface of stainless steel mesh catalyzing OER, was fabricated via electro-deposition method. This as-synthesized oxygen electrode was used directly for zinc-air battery assembly without polymer binders, which have low conductivity and suffer from detaching when immersion in alkaline solutions, leading to battery failure and short cycle life. In our system, the zinc-air battery was assembled with as-synthesized air cathode, 6M KOH/0.2M zinc acetate electrolytes and zinc foil anode. The battery was operated at the current density of 20 mA/cm2and its charge/discharge potential was 1.95V/1.15V, respectively. In addition, it showed stable performance with >80% coulombic efficiency over 1000 recharge cycles.
Acknowledgement: Authors would like to thank the Bureau of Energy (BOE), Ministry of Economy Affair (MOEA), Taiwan for the financial support.
References:
[1] J. W. D. Ng, M. Tang and T. F. Jaramillo. Energy Environ. Sci. 2014, 7, 2017.
[2] J. Masa, W. Xia, I. Sinev, A.Q. Zhao, Z.Y. Sun, S. Grutzke, P. Weide, M. Muhler, W. Schuhmann, Angew. Chem. Int. Ed. 2014, 53, 8508.
[3] S. Hu, T. Han, C. Lin, W. Xiang, Y. Zhao, P. Gao, F. Du, X. Li, and Y. Sun. Adv. Funct. Mater. 2017, 1700041.
High-Performance Supercapacitors Based on Graphitic Nanofibers/Nickel Sulfide Composite Electrodes
Authors: Tsai Yi-Hung , Chen I-Ching , Hsieh Chien-Kuo , Lin Jeng-Yu 
Published: February 2020

Fossil fuel depletion, environmental pollution, and global warming have attracted interest in developing green and replaceable energy storage devices. Among various energy storage devices, supercapacitors (SCs) have been widely recognized in a wide range of applications in energy storage over the past decade, such as electric vehicles, mobile electronic devices, large industrial equipment, memory backup systems, and military devices. It is due to their unique properties including high power capability, long cycle lifetime, and fast charge/discharge rate.
In this work, nickel sulfide (Ni3S2) nanosheets were growth on the surface of graphitic-nanofibres (GNFs) by using pulse-reversal (PR) electrodeposition method. Compared to the pristine Ni3S2 electrode with discharged capacitance of 461 F g-1, the GNFs@ Ni3S2 electrode revealed a higher capacitance of 635 F g-1 at the same charge-discharge current density of 0.5 mA cm-2. The GNFs@ Ni3S2 electrode still retained 79% of the capacitance at 0.5 mA cm-2 when it was charged/discharged at 4 mAcm-2. Furthermore, the GNFs@ Ni3S2 electrode showed great electrochemical stability. For instance, the GNFs@ Ni3S2 electrode displayed 90% of initial capacitance after the consecutive 200 cycles charged/discharged at current density of 0.5 mAcm-2.
Initiation of Intergranular Corrosion on Extruded AA6005 Aluminium Alloy with Low Copper Content
Authors: Kumari Shilpa , Walmsley John Charles , Lunder Otto , Nisancioglu Kemal 
Published: February 2020

6000-series aluminum alloys are normally resistant to intergranular corrosion (IGC). However, underaged alloys, containing Cu as little as 0.1%, may be susceptible due to grain boundary sensitization by precipitation of Cu-rich nanofilm and depletion of Si in certain tempers [1]. The purpose of this work is to understand the initiation mechanism of IGC on as received and modified surface of extruded alloy AA6005. Methods for surface modification consisted of metallographic polishing, argon sputtering and alkaline etching. IGC initiation and testing was performed according to the standard BS-ISO 11846, consisting of immersion in acidified NaCl solution (pH 1) for different periods. Initiation of IGC was slower on as-received surface compared to the modified surface. Glow Discharge Optical Emission Spectroscopy (GD-OES) analysis indicated this was due to the presence of an approximately 50 nm thick mixed metal oxide layer. IGC initiated at the primary α-Al(Fe,Mn)Si precipitates for all types of surfaces. However, these phases corroded rapidly in the test solution causing formation of dealloyed Cu on the exposed particle surface, which act as increasingly effective external cathode for IGC. The AlMgSiCu (Q-phase) precipitates, present as primary and secondary particles, were relatively stable in the test solution both against anodic oxidation and as cathodic sites. In fact, the Q-phase particles appeared to act as physical barriers against IGC propagation. These results were in accordance with earlier preliminary results for the Ar-sputtered surface [2].
References
[1] M. Hurlen Larsen, J. C. Walmsley, O. Lunder, and K. Nisancioglu, J. Electrochem. Soc., 157, C61 (2010).
[2] K.Shimizu, K.Nisancioglu, ECS Electrochemistry Letters, 3 (9) C29-C31 (2014).
On the Corrosion of the Lightweight Compositionally Complex Alloy Altivcr
Authors: Qiu Yao , Birbilis Nick 
Published: February 2020

In this work we report and discuss the corrosion and microstructure of the compositionally complex alloy (CCA), AlTiCrV. This alloy was designed have a low-density (5.06 g.cm-3) relative to high entropy alloys (HEAs). The description of a CCA is used as it is broader than the description of high entropy alloys (HEAs) which nominally require at least 5 elements. AlTiCrV is a single phase CCA of exceptionally high aqueous corrosion resistance. Electrochemicsal studies are presented herein, whilst the role and nature of the native surface oxide is elaborated, in the context of corrosion resistance. X-ray photoelectron spectroscopy was carried out indicating selective oxidation and un-oxidised metal incorporation into the surface film, in addition to surfaces being highly reactive. Such features are unique and believed to be relevant to CCAs and HEAs more generally, as also elaborated herein.
The Localised Corrosion Behaviour of Magnesium-Germanium Alloys Studied Using a Scanning Vibrating Electrode Technique
Authors: Williams Geraint , Glover Carol Frances , Liu Tony , Birbilis Nick , McMurray Hamilton Neil 
Published: February 2020

There is considerable current interest in identifying alloying elements for magnesium which produce an intrinsically corrosion resistant surface, thus precluding the need for additional protection by surface treatments and coatings. Recent work has demonstrated the promise of certain group IV and V elements as binary micro-alloying additions, which produce significant reduction in the corrosion rate of Mg 1,2. In the case of alloyed arsenic (As), a well-known cathodic poison, the reduced rate of corrosion is principally attributed to a profound suppression of cathodic activity on transition-metal impurity containing phases by inhibiting recombination of atomic hydrogen 3. Recent work has also demonstrated a similar phenomenon for Ge alloyed Mg 2, although the underlying reasons are less obvious than for the case of As. To clarify the role of Ge in significantly reducing the corrosion rate of Mg, an in situ scanning vibrating electrode technique (SVET) is herein employed to study localised corrosion behaviour of Mg-Ge alloys at open circuit conditions and during anodic polarisation when immersed in chloride containing aqueous solution. Upon immersion in the absence of external polarisation in aqueous solution containing concentrations of 0.5 M NaCl and below, SVET-derived area-averaged anodic current densities are shown to be extremely low, with no visible evidence of breakdown in the form of the dark filiform-like tracks reported over 24 h (and up to 90 h for a concentration of 0.1 M). However, when using concentrations of 1 M NaCl (aq) and greater, filiform-like localised corrosion features become established after initiation periods of ca.2 h or longer. In contrast to pure Mg, no cathodic activation of filament clusters are observed and residual tracks are shown to develop a white colour instead of the typical surface blackening observed on pure Mg. The addition of Ge is shown to strongly depress free corrosion potential (Ecorr) compared to pure Mg and it is proposed that it acts to maintain Ecorrbelow the apparent breakdown potential indefinitely for chloride ion concentrations of 0.5 M and lower. Under galvanostatic anodic polarisation, hydrogen evolution rates are significantly lower in comparison to pure Mg and no localised cathodic activity is detected for the duration of the experiment. In this respect the behaviour of Ge-alloyed Mg closely mirrors that of the Mg-As system, but with the benefit of intrinsic corrosion resistance bestowed by a non-toxic alloying addition.
References:
1. N. Birbilis , G. Williams, K. Gusieva, A. Samaniego, M.A. Gibson and H.N. McMurray, Electrochem. Commun., 34 (2013), 295.
2. R. L. Liu, M. F. Hurley, A. Kvryan, G. Williams, J. R. Scully and N. Birbilis, Nature Scientific Reports, 6: (2016) 2874.
3. G. Williams, H. Ap Llwyd Dafydd, H.N. McMurray and N. Birbilis, Electrochim. Acta, 219 (2016) 401.
Development of pH Sensing CFDE to Investigate Anodic Dissolution of Magnesium
Authors: Miyazawa Kei , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

Magnesium (Mg) is widely used as a large transportation and structural materials for their weight savings. However, Mg has large corrosion rate, and the hydrogen evolution occurs during the anodic dissolution of Mg. It was reported that the hydrogen evolution rate on Mg increases with noble potential from corrosion potential, which is called the Negative Difference Effect (NDE) 1-8). In order to analysis of the NDE phenomenon, Rossrucker et al.4) applied an electrochemical flow cell coupled to downstream analysis for investigation of the influence of pH alteration in the near surface region of dissolving Mg. In this method, the polarization measurement and simultaneous determination of the amount of dissolved Mg ions via inductively coupled plasma - mass spectroscopy. In the present study, we developed the pH sensing channel flow double electrode (CFDE) to monitor the pH changes on the Mg electrode due to the anodic dissolution. Schematic of the pH sensing CFDE is shown in Fig. 1. In the CFDE cell, the working electrode (WE) and detecting electrode (DE) were placed upstream and downstream in the channel. An Mg (1×4 mm2) and a W (0.1×4 mm2) were used for the WE and DE. The counter electrode (CE) was a Pt wire, which was set at channel outlet. The reference electrode was KCl-saturated silver/silver chloride electrode (SSE). The rest potential of W (DE) was measured for estimation of pH during the anodic dissolution of Mg (WE). The 0.1 mol dm-3 sodium sulfate solution (pH = 5.9) was used for the measurement. The degassing of the electrolyte solution was carried out for 1 h under an N2stream. A laminar flow condition was established in this measurement. Furthermore, the surface of WE was recorded by a USB digital microscope.
The anodic polarization curve measurement of Mg and pH measurement was carried out by developed system. It was confirmed that the increase of pH is corresponded to the increase of anodic current of Mg with hydrogen generation.

Reference

[1] G. Song, A. Atrens, D. Stjohn, J. Nairn, and Y. Li, Corros. Sci., 39, 855 (1997).
[2] R. L. Petty, A.W. Davidson, J. Am. Chem. Soc., 76, 363-366 (1954).
[3] G. Song, A. Atrens, D. Stjohn, X. Wu, and J. Nairn, Corros. Sci., 39, 1981 (1997).
[4] L. Rossrucker, A. Samaniego, J.-P. Grote, A. M. Mingers, C. A. Laska, N. Birbilis, G. S. Frankel, K. J. J. Mayrhofer, J. Electrochem. Soc., 162, C333-C339 (2015).
[5] G. S. Frankel, A. Samaniego, and N. Birbilis, Corros. Sci., 70, 104 (2013).
[6] G. Williams, N. Birblis, and H. N. McMurray, Electrochem. Commum., 36, 1 (2013).
[7] G. L. Song and A. Atrens, Ave. Eng. Mater., 1, 11 (1999).
[8] G. L. Song and A. Atrens, Ave. Eng. Mater., 5, 837 (2003).

Figure 1
Localized Corrosion: Passive Film Breakdown Vs. Pit Growth Stability
Authors: Frankel Gerald S. , Li Tianshu , Scully John R. 
Published: February 2020

A debate about the critical step in localized corrosion has raged for decades. Some researchers focus on the composition and structure of the passive film associated with the initial breakdown of the film, whereas others consider that the susceptibility to pitting is controlled by the pit growth kinetics and the stabilization of pit growth. The basis for a unified theory of pitting is presented here in which pit stability considerations are controlling under aggressive conditions (harsh electrolytes and extreme environments and/or susceptible microstructures) and the passive film properties and protectiveness are the critical factors in less extreme environments and/or for less susceptible alloys.
This work was supported as part of the Center for Performance and Design of Nuclear Waste Forms and Containers, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0016584.