bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Hydrogen Embrittlement on the Mechanical and Electrochemical Properties of Carbon Steel API 5L X65 in a CO2-Saturated 3.5 Wt.% NaCl Solution
Authors: Rodriguez Alvaro , Rozman Kyle , Ziomek-Moroz Margaret , Tylczak Joseph H.
Published: February 2020

The effect of hydrogen charging of carbon steel API 5L X65 (UNS K03014) used in natural gas pipelines was investigated. Metal specimens were cathodically charged at potentials below Ecorr at 40°C in CO2-saturated 3.5 wt.% NaCl solution, pH 4 for 24 hours prior to carrying out potentiodynamic polarization and tensile tests. Electrochemical experiments were used to calculate corrosion rates and elucidate active, active-passive, and passive regions. Furthermore, fracture and fatigue of the alloy was determined at 1 × 10−6 s−1 strain rate. Surface characterization of the fractured and corroded samples was conducted using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Results from hydrogen embrittlement-induced specimens were compared to a parallel study of uncharged specimens to understand the effect of hydrogen cathodic charging on carbon steel API 5L X65.
Corrosion Studies of 12-Aminododecanoate Modified Zn-Al LDH/Epoxy Coating
Authors: Aminifazl Alireza , Golden Teresa D
Published: February 2020

Addition of environmentally friendly layered double hydroxide (LDHs) to organic coatings can increase barrier properties within the coatings due to the platelet structure of the LDHs. A new approach combining silane coupling agents to enhance compatibility of the inorganic and organic matrix is used to form improved corrosion resistance coatings. For this work, Zn-Al-LDH are prepared via a co-precipitation method and modified by sodium 12-aminododecanoate through an anion exchange process. The organo-modified layered double hydroxide (LDH) is functionalized using 3-aminopropyltriethoxysilane (APTES) which is then incorporated into the epoxy matrix (EPON 828). The reaction between amine part of the amino dodecanoate as a strong nucleophilic group and epoxy ring part as an electrophilic group improves compatibility of LDHs layers and epoxy molecules in the composite. Differential scanning calorimetry is used to study this exothermic epoxy-amine ring opening reaction to determine the curing temperature of the coatings before and after modified LDH inclusion. The change in LDH structure, effect of incorporation of modified LDHs in the epoxy matrix, grafting of APTES on the LDH surface and elemental analysis are investigated respectively, by x-ray diffraction, thermogravimetric analysis, infrared spectroscopy and energy dispersive x-ray analysis. In the last step of preparation, Epikure 3571 as a curing agent, is added to the LDHs/epoxy system, then the coating is applied on steel substrates. After the thermal curing process, the anti-corrosion performance provided by this coating is assessed by multiple methods including, open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5% NaCl aqueous solution. Further, scanning electron microscopy is used to study morphological changes on the coating before and after immersion test and to scan the localized corrosion spots. The results are compared with the coated steel samples with clear epoxy coating and none modified LDH/epoxy.

Figure 1
Microstructural Evolution of 52M Weld Metal Near the Fusion Boundary and Oxide Films Formed in Simulated PWR Primary Water
Authors: Zhang Kun , Ma Jiarong , Ning Fei , Cui Tongming , Jia Yibo , Lu Zhanpeng
Published: February 2020

Environmentally assisted cracking of structural materials such as dissimilar metal welds in high temperature water environments is strongly affected by the surface oxide film formed in the operating environments. In the present work, Nickel-base 52M weld metal samples are taken from two dilution zones and undiluted zone, and the microstructure was analyzed. Oxide films formed on these samples immersed in simulated PWR primary water at 325oC for 100h. The films are duplex-layered with the outer layer consisted of larger and scattered particles, and the inner layer consisted of small and dense particles. With increasing the distance from FB, the number of larger particles of outer layer decreased while the appearance of smaller particle of inner layer changed into needle-liked particles. With the increase of distance, the proportion of needle-liked particles increase, but the larger particles became less angular. The inner layer became thinner while the size of larger particles of outer layer became smaller with the distance from FB increases. The outer layer was Fe-rich while the inner layer was Cr-rich. The change of element concentration resulted in different oxidization behavior in PWR primary water. The formation of larger particles of outer layer can influence the appearance of inner oxide film.

Figure 1
The Interdependent Deposit-Metal Interaction during Underdeposit Corrosion (UDC)
Authors: Shamso Ahmed Nabil , Abdullah Aboubakr Moustafa , Laycock Nick , Ryan Mary P.
Published: February 2020

Underdeposit Corrosion (UDC) is a major problem that faces the integrity of pipelines in the oil and gas industry, especially in sour environments (H2S- rich). Among the deposits, typically, present in sour environments, iron sulfides (FexSy) require particular attention due to their complex nature as well as their physical and chemical interaction with the bare steel, which affects the corrosion rate significantly. In this study, we investigate the changes in the surface morphology, chemical composition and electrochemical behavior of iron that is underneath sand and iron sulfides deposits. These changes are monitored after (i) potentiostatic growth of artificial pits (pencil electrode configuration), (ii) potentiostatic corrosion of an iron sheet, and (iii) a ZRA coupling of a steel-deposit pair. A scanning electron microscope coupled with an energy dispersive X-ray spectrometer (SEM/EDX) and Raman spectrometer are used to reveal the changes in the physical and chemical properties of the metal and deposits. Data are presented in terms of the deposit-metal interdependent physical and chemical changes as a function of the used deposit and the electrochemical tests.
Influence of Cations on Atmospheric Corrosion of Hot-Dipped Galvanized Steel
Authors: Liu Yipeng , Ooi Azusa , Tada Eiji , Nishikata Atsushi
Published: February 2020

The zinc-coated sheets are widely used in auto industries, especially for body parts. Corrosion caused to the body parts by sea salts and deicing salts such as NaCl, MgCl2 and CaCl2 has raised concerns of the automakers. The role of Mg and Ca cations in is still intriguing [1], and the corrosion products formed under such condition could rather prolong the service life of galvanized steels. In this study, by combining the non-destructive electrochemical impedance spectroscopy (EIS) method and morphology observation, the benefit of alkaline metal cations on enhancing the corrosion resistance of galvanized steels has been investigated through accelerated lab test.

A commercial hot-dip galvanized steel having the coating thickness of 10 μm was employed as the specimen. The amounts of chloride salts deposited on the specimen surface were 4.05 g/m2 for MgCl2, 4.75 g/m2 for CaCl2, and 5.00 g/m2 for NaCl so that the chloride amounts were fixed to be 3.05 g/m2. The salt coated specimens were exposed to the dry-wet cycling over 95 % RH (2 h) - 40 % RH (2 h) in the humidity chamber. EIS and polarization curves were measured at the certain intervals of the exposure to evaluate the stage of degradation of the coating. The corrosion products were examined by X-Ray diffraction (XRD) and scanning electron microscope with an energy dispersive X-ray detector (SEM-EDX).

The specimens deposited with MgCl2 exhibited far better corrosion resistance than those with NaCl. Even after 15 weeks (630 cycles), the open circuit potential held at around -0.9 V (vs. SSE), indicating the remain of metallic zinc coating. The corrosion rate estimated by EIS results was also low. This high corrosion resistance was ascribed to a thin and homogenous corrosion product layer, which was mainly composed of Zincite (ZnO) and Simonkolleite (Zn5(OH)8Cl2·H2O). After 126 cycles of the exposure, the corrosion products were turned to a double-layer structure of which the inner layer was dense and outer layer was porous. The compact inner layer must have offered the high corrosion resistance under the extended term of the aggressive environment. However, such a structure and long state of protection was not observed under NaCl salt films [2]. Alkaline metal chlorides are less aggressive to corrosion of the galvanized steel than NaCl and could promote the formation of homogenous corrosion product layer.

Reference

[1] Yumiko Tsurumaki, Eiji Tada, Azusa Ooi and Atsushi Nishikata, Anodic Polarization Behavior of Zn in Aqueous MgCl2 Solutions, 2018, ECS Meeting Abstracts, No. 1056

[2] Y. Liu, A. Ooi, E. Tada, A. Nishikata. Electrochemical Monitoring of Degradation Process of Galvanized Steels in Atmospheric Environments, 2018, ECS Meeting Abstracts, No. 1058

Figure 1
Electrochemical Test Configurations to Study Atmospheric Corrosion
Authors: Hangarter Carlos , Gong Bailey , Anderson Rachel M , Policastro Steve A
Published: February 2020

Atmospheric corrosion is one of the most difficult forms of corrosion to forecast. Although standardized exposures and accelerated tests exist for material characterization and prediction purposes, the premise of these approaches can be oversimplified to a fault that precludes utility. For instance, the concept of time of wetness is now recognized as a broad stroke parameter that distinguishes little about the rate of corrosion.1 Furthermore, many off-the-shelf systems and public weather services allow streaming of environment parameters such as relative humidity, temperature, wind speed/direction, solar radiation and precipitation. This deeper understanding of atmospheric corrosion processes and litany of meteorological information brings to question the best electrochemical approach(es) to characterize materials for atmospheric corrosion modeling.
In this work we examined three different electrochemical test configurations, show in Figure 1, to study atmospheric corrosion with polarization experiments that cover comparable parameter space. These experiments were tailored to the oxygen reduction reaction (ORR), the primary cathodic reaction in many corrosion systems, as literature data permits facile calculation of diffusion limited current under thin film electrolytes and forced convection. The first configuration consisted of an electrode stack with an oxygen permeable counter electrode placed in an environmental chamber, in which a wetted membrane fixed the electrolyte thickness. The second approach also required an environmental chamber to control film thickness but instead utilized microelectrodes to enable polarization with minimal disruption to the boldly exposed electrolyte surface. The third configuration deviated from the environmental chamber approach with a bulk electrolyte and rotating disk electrode to set the diffusion layer thickness with rotation rate.
These systems were all evaluated in chloride concentration relevant to atmospheric conditions. Polarization curves for different test configurations are examined in 2.7 M NaCl. While comparable, these configurations display distinct differences in iR drop, reproducibility and charge transfer resistance, which give rise to different open circuit potentials, Tafel slopes and diffusion limited behavior. These results will be discussed in terms of test configuration features to better understand applicability of different configurations, including practical limitations and potential for improvements/optimization.

1 Schindelholz, E., Risteen, B. E. & Kelly, R. G. Effect of Relative Humidity on Corrosion of Steel under Sea Salt Aerosol Proxies: II. MgCl2, Artificial Seawater. J Electrochem Soc
161, C460-C470, doi:10.1149/2.0231410jes (2014).

Figure 1: Photographs of each test configuration; membrane configuration (left), microelectrode configuration (center) and rotating disc electrode (right).

Figure 1
Chemical Mechanical Polishing Implementation for Corrosion Prevention of Titanium Bio-Implants
Authors: Basim G. Bahar , Yagan Rawana
Published: February 2020

Corrosion and surface film dissolution are two mechanisms for titanium-based bioimplants to release ions into the human body and hence degrading the biocompatibility. Electrochemical methods are commonly practiced in testing metallic biomaterials in-vitro measurements[1] (Kuhn, Neufeld and Rae, 1988). In an attempt to prevent the in-vivo corrosion of the titanium implants, we have introduced a new approach by utilizing chemical mechanical polishing (CMP) as a synergistic approach to form a protective surface film and as a tool to control the surface nanostructure [2] to promote or demote cell attachment.

In this paper, application of CMP on titanium implant surfaces is studied through electrochemical analyses in the absence and presence of an oxidizer. Corrosion rates are extrapolated from anodic polarization of the potentiodynamic curves (Figure 1) with and without CMP implementation to compare the affect of surface engineering. It was observed that the higher corrosion (Table 1) rates correlated to the higher material removal during polishing, which can be controlled through oxidizer concentration that affects the surface TiO2 film growth. Furthermore, potentiostatic measurements showed that the addition of oxidizer increased the rate of oxide growth and decreased the surface current density levels indicating that the surface self-passivation took place. Post CMP contact angle (wettability) and AFM measurements confirmed an improved surface topography and surface homogeneity by CMP treatment as better surface smoothness and wettability control was achieved.

[1] Kuhn, A., Neufeld, P. and Rae, T. (n.d.). Synthetic Environments for the Testing of Metallic Biomaterials. The Use of Synthetic Environments for Corrosion Testing, 1988, pp.79-79-19.

[2] Ozdemir, Z., Ozdemir, A. and Basim, G. (2016). Application of chemical mechanical polishing process on titanium based implants. Materials Science and Engineering: C, 68, pp.383-396.

Figure 1
Biodegradable Mg: Controlling the Corrosion Behavior By Biocompatible Coatings
Authors: Virtanen Sannakaisa
Published: February 2020

Magnesium and its alloys are promising materials for biodegradable implant applications. For successful applications, the degradation rate in the biological environment should match the healing behavior of the surrounding tissue. This presentation will discuss challenges in developing suitable coatings for Mg for biomedical applications, such as coatings based on biodegradable synthetic or natural biopolymers or different types of composite coatings (for instance: polymer/bioactive glass composite coatings). Immersion testing and electrochemical experiments revealed information on the corrosion protection properties of the coatings as well as on the time-dependent degradation of the coatings. Influence of the electrolyte composition on the performance of the coatings is being studied, as the type of simulated body solution used as well as addition of proteins can very strongly influence the corrosion behavior. The effects are highly complex in that for instance proteins show a time-dependent and strongly system-dependent influence on the corrosion rate. Moreover, interactions between the corroding surfaces and the biological environment will be discussed.
Dissolution Mechanisms of Mg Investigated By Various Electrochemical Methods
Authors: Itagaki Masayuki , Shitanda Isao , Hoshi Yoshinao
Published: February 2020

Magnesium and its alloys are widely used in the industrial fields such as the automobile and electronic devices because they have small density and high strength. However, it is also known that magnesium has large corrosion rate due to its less-noble electrode potential. Furthermore, hydrogen evolution rate on dissolving magnesium is increased with the anodic polarization, and it’s called “Negative Difference effect (NDE)” [1-4]. For example, Baril et al. [3] proposed the following dissolution mechanism of Mg2+ for an interpretation of NDE by a local impedance measurement.

Mg → Mg+
ads + e- (1)

Mg+
ads ⇄ Mg2++ e- (2)

Hydrogen evolution is accelerated by the following chemical reaction.

Mg+
ads + H2O → Mg2+ + OH- + 1/2H2 (3)

In this presentation, the dissolution and hydrogen evolution mechanisms of the pure magnesium in Na2SO4 and NaCl solutions were discussed on the basis of the following three electrochemical measurements: (1) 3D Impedance Spectroscopy, (2) Gas-Chromatographic Voltammetry [4], and (3) Channel Flow Double Electrode [5].

References

[1] R.L. Petty, A.W. Davidson, J. Kleinberg, J. Am. Chem. Soc., 76 (1954) 363-366.

[2] G. Song, A. Atrens, D. Stjohn, J. Nairn, Y. Li, Corros. Sci, 39 (1997) 855-875.

[3] G. Baril, G. Galicia, C. Deslouis, N. Pebere, B. Tribollet, V. Vivier, J. Electrochem. Soc, 154 (2007) C108-C113.

[4] Y. Hoshi, R. Takemiya, I. Shitanda, M. Itagaki, J. Electrochem. Soc., 163, (2016) C303 - C305.

[5] Y. Hoshi, K. Miyazawa, I. Shitanda, M. Itagaki, J. Electrochem. Soc. 165, (2018) C243 - C245.
Microstructure, Chemical Composition and Local Corrosion Behavior of Friction Stud Welding Joint
Authors: Gu Yanhong , Wang Shengnan , Gao Hui , Zeng Qunfeng
Published: February 2020

In this paper, X65 base metal and stud were joined by friction stud welding technology. Scanning vibrating electrode technique (SVET) and localized electrochemical impedance spectroscopy (LEIS) were performed to investigate localized corrosion behaviors of the welded joint. Scanning electron microscope (SEM), metallographic microscope and micro hardness tester were used to observe the microstructure and the hardness of the welded sample. Raman spectrometer and energy dispersive spectrometer (EDS) were used to determine the composition of the weldment before and after corrosion, respectively. The results show that the welded zone has the maximum micro-hardness and the densest microstructure. And the α-Fe2O3 and Fe3O4 were determined in the welded zone. The SVET and LEIS data indicate that the welded zone has the lowest current density and the largest impedance, this may due to the presence of iron oxides and the densest microstructure in the welded zone, showing the best corrosion resistance. The resistance between microstructure, micro-hardness, chemical composition and local electrochemical behavior were discussed.

Keywords: Friction stud welding; Raman; SVET; LEIS; X65 steel
Selective Electroless Copper Plating on a Polymer Substrate Via Magnetic Field Application
Authors: Danilova Sofya , Graves John Edward , Cave Gareth W V , Cobley Andrew J
Published: February 2020

Selective metallization of non-conductive materials is used in electronic device manufacturing. It is usually achieved via a combination of the photolithography and metal deposition processes. However, this approach is expensive and results in the production of hazardous waste. Present research suggests a cost-effective alternative way of selective metallisation, namely, a gradient magnetic field is applied during catalyst deposition, prior to electroless copper plating (Figure 1, A).

In order to enable an interaction with the magnetic field, the standard Pd/Sn catalyst was replaced by a novel magnetic catalyst, γ-Fe2O3-Ag composite nanoparticles (Figure 1, B). The catalyst was synthesised via a wet-chemical method at ambient conditions. The composition of the catalyst was confirmed by scanning electron microscopy and energy dispersive x-ray spectroscopy. The magnetic properties of the catalyst were confirmed whilst the catalytic activity towards formaldehyde oxidation was proven by cyclic voltammetry.

A gradient magnetic field was achieved by the combined application of a permanent magnet and steel template. The distribution of the magnetic field was simulated prior to template fabrication. The catalyst was attracted by the magnetic field and deposited only at the areas with maximum magnetic field influence. Subsequent electroless copper plating occured exclusively at the areas where the magnetic field was focused and catalyst deposited. Tracks of copper (350 µm width and 1 mm gap) were prepared using this novel additive manufacturing process (Figure 1, C).

Figure 1. A – schematic presentation of the process; B – novel magnetic catalyst γ-Fe2O3-Ag; C – selectively metallised substrate obtained by using novel magnetic catalyst and gradient magnetic field.

Figure 1
Electrochemical Co-Reduction of Ce (III) and Ga (III) and Preparation of the Intermetallic Compound in LiCl-KCl Eutectic
Authors: Yang Dawei , Han Wei , Li Mei
Published: February 2020

Molten salt as a kind of reaction media, which possesses high radiation stability and thermal stability, has been widely investigated in the nuclear field for the separation of lanthanides (Ln) and actinides (An). In this work, the electrochemical co-reduction of Ce (III) and Ga (III) on tungsten electrode at 773K was researched In LiCl-KCl-CeCl3-GaCl3 system by a series of electrochemical techniques, such as cyclic voltammetry (CV), square wave voltammetry (SWV) and open circuit chronopotentiometry (OCP). Three reduction signals were detected by CV and SWV, which showed the formation of Ga-Ce intermetallic compounds due to Ce deposited on the pre-deposited Ga film and reacted with Ga: Ga(III)+3e-=Ga and Ce(III)+3e-+xGa=CeGax. Then, Ce-Ga intermetallic compounds were prepared by potentiostatic electrolysis in LiCl-KCl-CeCl3-GaCl3 melts on molybdenum grid to establish the relationship between the composition of deposits and the equilibrium potential. The deposition products were analyzed by XRD and SEM-EDS. The results indicated two intermetallic compounds CeGa2 and CeGa6 were obtained by potentiostatic electrolysis at 0.34 V for 1.5 h.

Acknowledgments

The work was financially supported by the National Natural Science foundation of China (11675044, 11575047 and 21790373), the Major Research plan of the National Natural Science Foundation of China (91326113 and 91226201), and the International Exchange Program of Harbin Engineering University for Innovation−oriented Talents Cultivation.
"Buried" Surfaces: Membrane-like Coatings for Favorable Electrocatalytic Selectivity
Authors: Mei Bastian Timo , Endrodi Balazs , Smulders Vera , Gomes Adriano , Widlock Mats , Simic Nina , Mul Guido , Cornell Ann
Published: February 2020

For existing large-scale industrial processes (chlorate process) as well as emerging technologies (photocatalytic water splitting) electrochemical selectivity towards hydrogen evolution is essential to achieve high (energy) efficiencies. Electrode selectivity is widely reported to be achieved in the presence of solution additives such as sodium dichromate (Na2Cr2O7) [1]. In the chlorate process dichromate is known to form a thin membrane-like structure by reductive electrochemical deposition on the cathode. With the growing interest in the electrification of the chemical industry and the general need for clean energy technologies, the development of membrane-coated “buried” electrodes recently received increasing attention [2].

In this presentation, 1) the formation of amorphous oxide electrode coatings from chromate solutions will be described and 2) potential alternative coatings, particularly coatings derived from permanganate and vanadate electrolyte additives, will be introduced [3,4]. It will be shown by different electroanalytical techniques that these amorphous oxide overlayers are selectively permeable to certain electroactive species (Figure 1) and enable efficient hydrogen evolution without significantly altered kinetics.

References

[1] V. Smulders, N. Simic, A.S.O. Gomes, B. Mei, G. Mul, Electrochim. Acta, 2018, accepted; [2] D.V. Esposito, ACS Catal.,
2018, 8, 457-465; [3] B. Endrődi, V. Smulders, N. Simic, M. Wildlock, G. Mul, B. Mei, A. Cornella, Appl. Catal. B, 2018, DOI: 10.1016/j.apcatb.2018.11.038; [4] B. Endrődi, S. Sandin, V. Smulders, N. Simic, M. Wildlock, G. Mul, B. Mei, A. Cornell, J. Clean. Prod. 2018, 182, 529-537.
Organic Contamination on Ionic Liquid Polymer Brush and Its Analysis By Raman Spectroscopy
Authors: Kanematsu Hideyuki , Oizumi Atsuya , Sato Takaya , Kamijo Toshio , Honma Saika , Barry Dana M. , Ogawa Akiko , Hirai Nobumitsu , Kogo Takeshi , Kuroda Daisuke , Tsunashima Katsuhiko , Yoshitake Michiko
Published: February 2020

The contamination on materials surface leads to various industrial problems and our daily lives' ones. Therefore, many countermeasures have been investigated from industrial viewpoints. Biofouling by bacterial activities and biofilms formed on materials' surfaces as a result would be the main cause to fix many kinds of contaminations on them as well as themselves as contaminants. We proposed an ionic liquid polymer brush coating as countermeasure and found this as an effective anti-contamination coating. The characteristics of the contaminants by biofouling is that the surface products are composed of organic polymeric substances such as polysaccharides, proteins, nucleic acids and lipids. In this study, we analyzed the contaminants on the ionic liquid polymer brush coating, using Raman spectroscopy. And we also observed and analyzed what kind of polymeric substances would be removed from the brush surfaces by water washing.
Binder Degradation in Sodium- and Potassium-Oxygen Batteries
Authors: Braga Filipe , Hardwick Laurence J.
Published: February 2020

Non-aqueous sodium- and potassium-oxygen batteries (Na/K-O2) are promising candidates for alternative energy storage based on higher theoretical specific energy over conventional lithium-ion batteries1-2. The cell operation following the one electron reduction/oxidation of the metal superoxide (NaO2 and KO2) allows low charge polarisation and high columbic efficiency, which are some of the main challenges in the lithium-oxygen (Li-O2) counterpart. However, parasitic reactions between cell components and metal superoxides are still to be fully investigated and better understood. The present work accomplished a study of the electrochemical performance and characterised the discharge products in ether-based cells operating with porous carbon cathodes cast with different polymeric binders. When utilising poly(tetrafluoroethylene) (PTFE) and carboxymethylcellulose sodium (CMC), superoxide was detected via Raman spectroscopy as the main reaction product in both sodium and potassium systems. Poly(vinylidene fluoride) (PVDF), which is known to be unstable in the chemical environment of metal-oxygen cells3, was found to only affect the discharge/charge potential profile and reaction mechanism of Na-O2 cells but not K-O2. This is the result of a negative synergistic effect between PVDF dehydrofluorination reaction and the NaO2 dissolution/ionisation, which increases the formation of hydroperoxyl radical (HO2). HO2 is an intermediate reactive species in the oxidative decomposition reaction of the ether electrolyte. The formation of sodium carbonate and sodium formate results as parasitic products that are only oxidised at large overpotential, as detected via FTIR analysis. In K-O2 cells utilising PVDF binder, the desired reaction product formation is confirmed via XRD and SEM/EDS analysis, despite the detection of identical PVDF decomposition via Raman spectroscopy. As such, we will highlight how interplay of all cell components drives the overall reversibility of the desired oxygen electrochemistry in metal-air cells.

References

Adelhelm, P.; Hartmann, P.; Bender, C. L.; Busche, M.; Eufinger, C.; Janek, J., From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries. Beilstein journal of nanotechnology
2015,
6 (1), 1016-1055.

Xiao, N.; Ren, X.; McCulloch, W. D.; Gourdin, G.; Wu, Y., Potassium Superoxide: A Unique Alternative for Metal–Air Batteries. Accounts of chemical research
2018,
51 (9), 2335-2343.

Black, R.; Oh, S. H.; Lee, J.-H.; Yim, T.; Adams, B.; Nazar, L. F., Screening for superoxide reactivity in Li-O2 batteries: effect on Li2O2/LiOH crystallization. Journal of the American Chemical Society
2012,
134 (6), 2902-2905.

Figure 1
Ceramic-Polymer Interaction in Solid-State Composite Electrolytes of Lithium Ion Batteries
Authors: Yang Hui , Wu Nianqiang
Published: February 2020

Based on three dimensional (3D) pervoskite-type Li0.33La0.557TiO3 nanofibers and polymer, a composite solid state electrolyte has been fabricated. Our study shows that the ceramic-polymer interface has significant effect on the ionic conductivity of composite electrolytes and the cyclic performance of symmetric half cells. After a buffer later has been incorporated between the ceramic fibers and polymer matrix, the flexible solid-state electrolyte composite membrane exhibits high ionic conductivity at room temperature, a large electrochemical stability window and good mechanical stability in symmetric Li|electrolyte|Li cell.
Low-Cost Self-Assembled Oxide Separator for Rechargeable Batteries
Authors: Grundish Nicholas Spencer , Amos Charles Dallas , Khani Hadi , Agrawal Ankit , Goodenough John Bannister
Published: February 2020

Rechargeable battery cells having a liquid electrolyte require a separator permeable to the electrolyte between the two electrodes. The volume changes of the electrodes during charge and discharge have previously limited porous separators to polymers with an electronic energy gap Eg large enough for the Fermi levels of the two electrodes to be within it. We demonstrate that the plasticity of a costly polymer membrane is not needed for the separator in a liquid electrolyte. SiO2 is an insulator with the required large energy gap, and SiO2 particles are easy to prepare, cheap, and environmentally friendly. We demonstrate that removal of adsorbed species from the surface of a film of SiO2 nanoparticles leads to weak bonding between the particles to give a self-assembled, porous layer that has the needed plasticity for a liquid-electrolyte separator that is wet by an alkali-metal anode.
Single-Step Preparation of Li2S-C Composite Electrode for Sulfide Based All-Solid-State Battery
Authors: Chang Gi Hwan , Lim Hyung-Tae
Published: February 2020

Performance of all-solid-state batteries (ASSBs) is limited by high interfacial resistance as a result of rigid solid-solid contact between electrolyte and electrode particles. Thus, it is necessary to increase the pathways for lithium ion and electrons transport, securing intimate solid-solid contact. Electrode fabrication procedure is one of critical steps to determine kinetic properties of ASSBs. The electrode preparation is usually step-wise and complex so that it needs to be simplified without sacrificing performance. In the present work, ASSB cells, consisting of Indium counter electrode, sulfide-based glass (Li2S-P2S5) electrolyte and lithium sulfide composite (Li2S + acetylene black) working electrode, were fabricated. Lithium sulfide composite electrode was prepared by two different ways, multi-step and single-step. Charge-discharge tests were conducted under a constant current 200 ~ 600 μA (130 ~ 390 μA/cm2) to compare kinetic properties of lithium sulfide composite electrode prepared by multi-step and single-step. SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy) mapping and Raman spectroscopy were also performed to analyze particle distribution and morphology of the composite electrodes.
Mitigating Storage-Induced Degradation of LiNi0.8Co0.1Mn0.1O2 for Lithium-Ion Batteries Via Surface Tuning with Phosphate
Authors: Ryu Won-Gyue , Shin Hyun-Seop , Park Min-Sik , Jung Kyu-Nam , Lee Jong-Won
Published: February 2020

Driven by strong demands for long-range electric vehicles, extensive efforts have been devoted to design and develop advanced cathode materials with high capacity and high operating voltages. Given the commercialization possibility on an industrial scale, Ni-rich layered transition metal oxides, such as LiNi0.8Co0.1Mn0.1O2 (NCM811), with a high specific capacity, may be a reasonable choice. However, due to its inherent structural/chemical/electrochemical instability, NCM811 with high Ni content suffers from significant performance degradation upon storage even in ambient atmospheres as well as during charge–discharge cycling. Herein, we demonstrate a simple but effective surface-tuning approach to mitigate storage-induced degradation of NCM811, which is based on the conversion of undesirable Li residues to a protective Li3PO4 nanolayer via phosphate treatment. The accelerated storage stability test (ASST) shows that phosphate-modified NCM811 exhibits remarkably improved electrochemical performance (capacity, cycle life, and rate capability) over the pristine one after being stored under harsh environmental conditions. Based on the ASST studies combined with material characterizations (SEM, TEM, and XPS), the enhanced cycling and storage stability of phosphate-modified NCM811 is explained as follows. First, phosphate treatment eliminates Li residues that can easily be transformed to undesirable impurity phases such as Li2CO3 and LiOH. Second, a thin Li3PO4 nanolayer produced by the chemical reaction between residual Li and (NH4)2HPO4 effectively mitigates the parasitic electrolyte decomposition by preventing the direct contact between NCM811 and electrolyte. Third, the formation of Li3PO4 contributes to the increased ordering of the layered structure (i.e., reduced cation mixing). Finally, Li3PO4 serves as an effective protecting layer for H2O and CO2 infiltration during storage, thereby suppressing the deterioration of particle integrity.
Double-Doped Porous Perovskite La0.6Ca0.4Fe0.8Ni0.2O3 Nanofibers As a High Efficient Bifunctional Catalyst for Rechargeable Lithium-Oxygen Batteries
Authors: Wang Ziling , Zou Lu , Li Ruizhu , Li Jin , Chi Bo , Pu Jian , Li Jian
Published: February 2020

Lithium-oxygen batteries (LOBs) are considered as one of the most promising electrochemical devices on account of their extremely highest specific energy density. However, it is confronted with significant challenges on their practical development and application due to poor electrocatalytic activities of the cathode catalysts toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In order to increase the actual capacity of LOBs, the cathode catalyst not only needs to have better catalytic activity but also has a high surface area and a large pore volume which is used to store Li2O2 to increase the discharge capacity. In this paper, two methods to prepare the doped La0.6Ca0.4Fe0.8Ni0.2O3 perovskite, are both electrospinning technique (denoted as f-LCFN) and sol-gel method (denoted as s-LCFN). And after N2 adsorption and desorption experiments, it can be found that the f-LCFN has a richer mesoporous structures comparing with the s-LCFN. The total pore volume and BET surface area of f-LCFN are 0.14 cm3 g-1 and 31.5 m2 g-1, respectively, which are larger than those of s-LCFN (0.99 cm3 g-1 and 20.76 m2 g-1). Previous study shows that at a current density of 200 mAg-1, s- LCFN has a higher specific discharge capacity (7827.88 mAhg-1) and a potential plateau at 2.2 V, which maintain stable after 34 cycles under a limited discharge depth of 500 mAhg-1. According to the previous SEM test results, the f- LCFN is a hollow nanowire. The electrical performance of f- LCFN will be tested later.

Figure 1
Electrochemical Properties and Analysis of High Performance Nano-LiCoO2
Authors: Ashuri Maziar , He Qianran , Segre Carlo , Shaw Leon
Published: February 2020

The long-term cycle behavior of nano-LiCoO2 cathodes over 500 cycles at high rates is investigated. The post-mortem analysis of the cycled nano-LiCoO2 cathodes using a combination of X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) shed light on the capacity decay mechanisms. It is found that crystalline nano-LiCoO2 after 500 charge/discharge cycles at 10C becomes amorphous, exhibits Co2+ species rather than the expected Co3+ at the fully lithiated condition, has longer Co-O bond length than pristine nano-LiCoO2 and micro-LiCoO2, and shows 53% specific capacity loss over 500 cycles at 10C. In addition, slow Li-ion intercalation and de-intercalation at the electrode/electrolyte interface are found to be the rate-limiting step for nano-LiCoO2 during discharge and charge, respectively. Thus, to achieve the high rate capability of LiCoO2, not only LiCoO2 particle sizes should be reduced to nanoscales, but also the Li-ion intercalation and de-intercalation rates at the electrode/electrolyte interface need to be enhanced.
Fabrication and Characterization of Highly Ordered Graphite Nanofiber Network Structure for Lithium-Sulfur Batteries
Authors: Lee Dong Kyu , Jeon Hwan-Jin , Ahn Chi Won
Published: February 2020

Graphitic carbon fiber felt (GCFF) with a highly ordered crystalline graphitic carbon structure was fabricated by a combination of electrospinning and graphitization (2800 °C heat treatment) of carbon precursor polymer (PAN; Polyacrylonitrile) and was used as an interlayer between the cathode and separator in Li-S batteries. This GCFF interlayer trapped the polysulfides on the cathode side and increased the utilization of sulfur by suppressing the shuttle phenomenon. Also, the GCFF was shown to be able to act as an upper current collector to reduce the charge-transfer resistance owing to the high crystallinity of the graphitic carbon fibers. The sulfur cathode with the GCFF interlayer showed a high specific initial discharge capacity of 1280 mAh g−1 and excellent cycling stability (1004 mAh g−1 after 100 cycles) at 0.2 C. Also, an image of the glass fiber (GF) separator on the anode side confirmed the presence of an SEI(solid-electrolyte interphase) after 200 cycles, which apparently resulted from stable Li deposition on the Li metal because of the low or medium concentration of sulfur in the electrolyte solution. Our observations should contribute to elucidating the key features of complex three-dimensional carbon fabrics with crystalline graphitic structures that allow them, when inserted as interlayers, to markedly improve the performance of rechargeable batteries.

Reference: Journal of Power Sources, Volume 360, 31 August 2017, Pages 559-568
Carbon Quantum Dots Deposed on TiO2 Hollow Spheres for Lithium-Ion Battery Anodes
Authors: Martinez-Morales Alfredo , Lee Seungjin
Published: February 2020

Lithium-ion batteries (LIBs) have been studied for decades and play an important part in many of our daily activities. However, the demand for higher energy capacity and power density continues to increase, particularly in applications such as electric vehicles (EVs). To satisfy the demands of applications operating at high currents and high power, the development of electrode materials with high power density is required. Owing to its abundance, long cycle life, and low cost, titanium dioxide (TiO2) has been intensively investigated as an anode material. Moreover, TiO2–based anodes exhibit two advantageous properties: 1) a relatively high lithium insertion/extraction voltage (higher than 1.5 V vs. Li+/Li); and, 2) the prevention of lithium plating on the anode. Both characteristics improve the safety of the batteries compared to the use of a lithium metal anode. However, because of the low conductivity of TiO2, it shows poor performance as an anode material for lithium ion batteries. To overcome this limitation, graphene substrates can be used to boost the electrochemical performance of TiO2 since they can enhance the electronic conductivity in the electrode. Unfortunately, the drastic volume expansion and disintegration of graphene surface during charge/discharge is a main obstacle to this approach. Therefore, the particle size and dispersion of graphene substrates are key factors for improving anode conductivity and reliability.

Herein, we report a strategy to improve the electrochemical performance of TiO2 and prevent the volume expansion suffered by graphene substrates by combining TiO2 hollow spheres with carbon quantum dots (CQDs) that possess high conductivity and good dispersion. Mesoporous TiO2 hollow spheres are prepared by a sol-gel method using SiO2 spheres as sacrificial templates. The TiO2 hollow spheres provide not only the porosity, but also the large surface area needed to enhance the attachment of CQDs. The CQDs are attached on the surface of TiO2 hollow spheres by a hydrothermal treatment (CQDs@TiO2). These hybrid nanoparticles exhibit higher conductivity and less volume expansion due to their porous .

The size of the CQDs@TiO2 was determined to be about 200 nm by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The crystallinity of CQDs@TiO­2 were confirmed by X-ray diffraction (XRD), showing anatase crystal structure. The surface area and pore size distributionwere characterized CR2032-type coin cells are assembled by using the CQDs@TiO2 active materials and LiFePO4 (as the cathode material). Electrochemical properties are characterized by cycling under different C-rates and charging/discharging profiles.
Electrochemical Investigations of High Voltage Na4Ni3(PO4)2P2O7 Cathode for Sodium Ion Batteries
Authors: Petla Ramesh Kumar , Amin Ruhul , Belharouak Ilias , Sougrati Moulay Tahar , Ben Yahia Hamdi , Essehli Rachid
Published: February 2020

Sodium ion batteries (SIBs) are attractive candidates because of their low cost and their electrochemistry that is similar to the well-established lithium-ion technology [1]. Development of new cathode materials with high voltage and high capacity with good electric and ionic conductivity is critical to enhance power densities of the SIBs [2]. We are reporting the electrochemical performance of a polyanionic material Na4Ni3(PO4)2P2O7 as a potential high voltage cathode for rechargeable Na-ion batteries. The pristine and carbon coated materials [Na4Ni3(PO4)2P2O7-rGO and Na4Ni3(PO4)2P2O7-C] were prepared by a sol-gel method and were characterized by using galvanostatic charge-discharge cycling at different conditions (variable cut of voltages, interval times, fixed capacities) [3]. Carbon coated Na4Ni3(PO4)2P2O7 sample delivers a stable discharge capacity of 51 mAh g−1 at 0.1 C rate after 40 cycles (1.3 Na ion was intercalated/de-intercalated) (Figure 1). In-situ Powder XRD data were collected during the first charge and discharge cycles. The results indicate the presence of a reversible structure change after the first cycle. More details will be provided during the meeting.

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Figure 1
New Electrolyte Additives for High Voltage Lithium Ion Batteries
Authors: Lyu Hailong , Li Yunchao , Jafta Charl J , Bridges Craig A. , Meyer Harry M , Borisevich Albina , Paranthaman Mariappan Parans , Dai Sheng , Sun Xiao-Guang
Published: February 2020

The degradation of lithium ion batteries (LIBs) with cycling results from reactions of electrolyte at both anode and cathode, leading to increased cell impedance from continual formation of solid electrolyte interphases (SEIs). One of the economic ways to improve battery cycling performance is to utilize sacrificial additives that could form thin and stable SEIs to prevent continual electrolyte reactions at both electrodes. In this presentation, three trimethylsilyl based malonate esters have been used as additives in 1.0 M LiPF6/ethylene carbonate (EC)-dimethyl carbonate (DMC)-diethyl carbonate (DEC) (1-1-1, by v) baseline electrolyte for LiNi0.80Co0.15Al0.05O2 (NCA) based high voltage lithium ion batteries. The NCA half-cells with 5 wt.% additive exhibit higher capacity retention than that in the baseline electrolyte at different upper cut off voltages, that is, 4.2, 4.3, 4.4 and 4.5 V vs. Li/Li+. Scanning electron microscope (SEM) show that the additive successfully prevents the formation of thick solid electrolyte interphase (SEI) films on the surface of the NCA electrodes. X-ray diffraction (XRD) further reveals that the crystal structure of NCA is also maintained in the electrolyte with 5 wt.% additive at high cut off voltages. Besides beneficial to NCA cathode, the BTMSMFM additive also ensures better cycling performance of the graphite based half-cells and NCA/graphite full-cells, and thus is a promising additive for application in rechargeable lithium ion batteries.
Surface Modification of Carbon Fiber Interlayer Via Amide Coupling Reaction for High-Performance Lithium-Sulfur Batteries: Experimental and Theoretical Investigation
Authors: Kosasang Soracha , Ma Nattapol , Chiochan Poramane , Duangdangchote Salatan , Gatemala Harnchana , Chanlek Narong , Sawangphruk Montree
Published: February 2020

Lithium-sulfur battery (LSB) is a promising candidate as a conventional lithium-ion battery replacement due to its high theoretical specific capacity and high energy density together with additional advantages of low cost, abundance, and environment friendliness. However, LSB still suffers from many issues including natural insulator of active sulfur and final product of Li2S, polysulfide shuttle effect, and 80% volume expansion during cycling which are causes of capacity fading in the LSB. To fix the mentioned issues as well as improve performances of LSB, carbon interlayer has introduced between a sulfur cathode and separator to suppress lithium polysulfide diffusion and act as an upper current collector. Here, we prepare surface modified carbon fiber paper (CFP) via a simple amide coupling reaction with various amine reactants to study the effect of functional groups on the surface of the CFP on LSB performances. LSB with modified CFPs as interlayers show significant higher specific capacity than LSB without interlayer due to the chemisorption ability between functional groups on the CFP surfaces and lithium polysulfide intermediates. The LSB with modified CFP by 4-aminobenzoic acid interlayer exhibits the highest specific capacity along with long cyclability observed from high capacity retention of 88.5% and Coulombic efficiency above 98% after 200 cycles. Furthermore, the lithium polysulfide chemisorption capabilities of each functional group are fundamentally explained via density functional theory (DFT) calculations through the binding energy between functional groups and polysulfide intermediates. More interestingly, we also prove that the excellent performance of the LSB with 4-aminobenzoic acid interlayer is due to the strong lithium bond of S-L…O coupled with hydrogen bond of S…H-O.
Microstructural Analysis of Li-Ion Battery Graphite Anodes
Authors: Norris Chance , Mistry Aashutosh N , Roberts Scott A. , Mukherjee Partha P.
Published: February 2020

Lithium-ion batteries are canonically designed to be cathode-limited. However, the deleterious effects are anode-centric1-3. The conventional wisdom about porous intercalation electrodes treats them as homogeneous reaction zones with spherical particles undergoing intercalation. Graphite anodes exhibit a considerable morphological departure from this interpretation. In the present work, multiple graphite electrode tomograms are analyzed for their microstructural variation. The associated geometrical stochasticity is quantified in terms of short- and long-range interactions to provide a comprehensive picture of its electrochemical response.

(1) Zheng, H.; Qu, Q.; Zhu, G.; Liu, G.; Battaglia, V. S.;Zheng, H. Quantitative Characterization of the Surface Evolution for Lini0. 5co0. 2mn0. 3o2/Graphite Cell During Long-Term Cycling. ACS Appl. Mater. Interfaces
2017, 9, 12445-12452.

(2) Mistry, A. N.; Smith, K.;Mukherjee, P. P. Electrochemistry Coupled Mesoscale Complexations in Electrodes Lead to Thermo-Electrochemical Extremes. ACS Appl. Mater. Interfaces
2018, 10, 28644-28655.

(3) Kotak, N.; Barai, P.; Verma, A.; Mistry, A.;Mukherjee, P. P. Electrochemistry-Mechanics Coupling in Intercalation Electrodes. J. Electrochem. Soc.
2018, 165, A1064-A1083.