bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructual and Chemical Analysis of Surface Treated Metal Foam Anode for Li Rechargeable Battery
Authors: Ahn Tae-Young , Choi Yu Song , Kim Jiyoun , Cho Jang-Hyeon 
Published: May 2020

As the amount of power consumed by electronic products increases, a lot of studies focused on high capacity and miniaturization of batteries. In order to overcome the low capacity of carbon anode in Li rechargeable battery, researches on the development of high capacity anode material have been conducted. In particularly, it has been reported that pure lithium was adopted for high capacity of Li ion battery due to its light in weight and excellent theoretical capacity. However, when pure lithium is used, the capacity decreases rapidly as charging and discharging proceeded, which is reported to be formation of dendrite on the Li surface during charging/discharging. In order to suppress the growth of dendrite during charging/discharging, several researches have been focused on the Li impregnated metal foam for Li rechargeable battery. However, due to the poor wettability between metal foam and pure Li, adhesive materials had to be deposited by using expensive processes such as chemical vapor deposition to impregnate the Li into metal foam.
In this study we focus on the heat treatment effect on the microstructure and Li-impregnation property of Ni metal foam. We oxidized the metal foam in a high temperature(500-900oC) for 5 min using the furnace to improve the wettability between the Lithium and Ni metal foam. Heat treated metal foam was dip into melted Li at 400 oC in a glove box. As a result, the rate of Li-impregnation in the heat treated metal foam was more than 10 times faster than that of the untreated Ni metal foam. The surface of heat treated Ni metal foam was characterized using transmission electron microscopy (TEM) equipped with energy dispersive X-ray spectroscopy(EDS). Figure. 1 shows the TEM image of the untreated and heat treated Ni metal foam surface. It reveals that an additional layer having a thickness of 200 nm was observed in the heat treated Ni foam. The additional layer was identified as polycrystalline NiOx by EDS and selected area diffraction pattern (SADP). It is believed that formation of NiOx was greatly contribute to improvement of the impregnation characteristics. In addition, the impregnation characteristics of Ni alloy foam will be discussed in this presentation.

Figure 1
Flexible Self-Chargeable Sodium-Ion Battery for Soft Electronics
Authors: Zhou Dan , Wang Ning 
Published: May 2020

Exploring the concept of soft energy unit with improved sustainability and flexibility is critically important for the development of wearable electronics that comes into direct contact with human tissues. In this work, a flexible and self-chargeable sodium-ion full battery was developed by coupling elastic piezo-films with the separator of flexible sodium-ion batteries. This new device achieves excellent flexibility and self-charging performance. It can not only be charged to about 0.65 V under mechanical bending in 150 s or palm patting within 300 s, but also demonstrates interesting self-charging behavior even with quasi-static pressing. In the latter case, the self-charging rate increases with the rising of the applied static forces, which can be ascribed to the sound elasticity of the piezo-film. This work contributes to the development of flexible and self-chargeable electrochemical power devices for soft wearable electronics.
Reference
[1] D. Zhou, L.P. Xue, L. Wang, N. Wang, W.-M. Lau, X. Cao. Nano Energy 2019, 61, 435–441.
[2] N. Wang, W. Dou, S. F. Hao, Y. Cheng, D. Zhou, X. M. Huang, C. Jiang, X. Cao. Nano Energy 2019, 56, 868–874.
[3] D. Zhou, L.-P. Xue, N. Wang. J. Alloys Compd. 776 (2019) 912-918.

Figure 1
Effect of Zn2+ on Cathodic Reaction of Carbon Steel in Aqueous MgCl2 Solutions
Authors: Tada Eiji , Ooi Azusa , Nishikata Atsushi 
Published: May 2020

We have shown that zinc dissolution is accelerated in relatively high concentrations of MgCl2 during the galvanic corrosion process consisting of zinc and carbon steel. In this study, in order to understand further the galvanic corrosion process of zinc and carbon steel in MgCl2, the cathode reaction on carbon steel was investigated in MgCl2 aqueous solution with and without Zn2+ which is generated during the galvanic corrosion process.
The sample used for the experiment was carbon steel SS400 (Fe-0.12C-0.60Mn-0.011P-0.019S) machined to a shape of 1.5 × 1.5 × 0.3 cm3. One side of this sample was ground up to #2000 grit with SiC abrasive papers and then degreased and washed in acetone before use in the following experiments. The test solutions were mixtures of 0.25 M MgCl2 and x mM ZnCl2 (x = 2.5, 5 mM, Mg / Zn molar ratio: 100, 50) and they were used at room temperature under a naturally aerated condition. As reference solutions, the mixtures of 0.5 M NaCl and y mM ZnCl2 (x = 5, 10 mM, Na / Zn molar ratio: 100, 50) with the same Cl- concentration were used. The cathodic polarization curve measurements were done by a conventional three-electrode method with a platinum wire as a counter electrode and an Ag / AgCl electrode (saturated KCl, SSE) as a reference electrode. The potential sweep rate was 0.5 mV/s
On the cathodic polarization curves for carbon steel measured in an aqueous MgCl2 solution containing Zn2+, the diffusion-limiting current region due to the cathodic reduction reaction of dissolved oxygen (ORR) was observed from -0.6 V to -0.8 V, and the magnitude of the limiting currents were almost the same regardless of the Zn2+ concentration. Furthermore, the cathodic polarization curves showed that an increase in the current due to the hydrogen evolution reaction (HER) occurred in the MgCl2 solution without Zn2+. By comparison with the cathodic polarization curve measured in the NaCl solution without Zn2+ showed a diffusion-limiting current of ORR was comparable to that in the MgCl2 solution, but the overvoltage of HER was increased by about 0.1 V. These results indicated that in the MgCl2 solution, HER on carbon steel was enhanced more than that in NaCl aqueous solution.
On the other hand, in the MgCl2 solutions containing Zn2+, a shoulder was observed in the cathode polarization curve at around -0.95 V, and the the current due to HER was decreased with increasing the Zn2+ concentration. It was shown that HER was suppressed in MgCl2 solutions by the presence of Zn2+. This may be attributed to the precipitation of zinc corrosion products formed during cathodic polarization.
Composite Epoxy Coating Reinforced by Silane-modified Micro-Al2O3 Particles for Long-time Anti-corrosion Protection in Solution of Seawater Salinity
Authors: Lu Qingye , Yu Mingdong 
Published: May 2020

Marine pipelines in subsea oil and gas production systems are exposed to very corrosive high salinity condition and demand high anti-corrosion coatings. Superhydrophobic particles have long been used to make the rough structure of the superhydrophobic surface for anti-corrosion protection. Epoxy coatings are considered to be one of the best protective method for metals because the epoxy resins have very good chemical resistance, strong adhesion to the substrate, good mechanical and insulating properties. However, the application of epoxy coatings has been limited in many cases due to their characteristics such as brittleness and sensitivity to micro-cracks owing to their three-dimensional network structure, low impact toughness, and poor fatigue property. In recent years, second phase particles for toughening the epoxy matrix have attracted a lot of attention. A noticeable increase in both the shear strength and adhesive peel strength appeared mainly due to high levels of dispersion of the high modulus nanoparticles and effective interfacial interactions with the epoxy matrix. Many studies have reached similar conclusions.
So far, numerous studies have been performed to determine the effect of adding reinforcement inorganic particles on the wear and erosion resistance of the epoxy coatings, and the electrochemical characterization of those particle-reinforced epoxy coatings was normally studied for short exposure time. However, no studies have been carried out on the corrosion resistance properties of superhydrophobic particle-reinforced epoxy coatings with long exposure time in corrosive solution.
This work aims the development of superhydrophobic micro-Al2O3 as reinforced particles for epoxy coating under long-time exposure to solution of seawater salinity, and comparison of the effects of using hydrophilic and superhydrophobic micro-Al2O3 as reinforced particles on the protection property of epoxy coating. Epoxy composites filled with both silane functionalized Al2O3 (SF-Al2O3) and unfunctionalized Al2O3 (UF-Al2O3) were fabricated at a filler loading of 26 vol.% micro-particles. The SF-Al2O3 particles exhibited a water contact angle of 156.5°. Electrochemical testing including open circuit potential, impedance and phase angle measurements showed that SF-Al2O3 epoxy have better corrosion resistance as compared to pure epoxy after 144 d immersion in solution of seawater salinity (3.5 wt% NaCl), while the coatings with UF-Al2O3 showed failure after 36 d immersion. Scanning electron microscope analysis revealed a very good condition of the SF-Al2O3 epoxy coating after 144 d immersion. It is clearly observed that silane-modified particles were very effective on the anti-corrosion protection property of composites in high salinity solution. The results may have important implications for the design of particles reinforced polymeric composite coatings.
Photoelectrochemical Cathodic Protection Effect of Bi2S3/TiO2 nanorod Array Composite Film for Stainless Steel
Authors: Du Rong-Gui , Hu Juan , Jin Piao 
Published: May 2020

TiO2 nanomaterials have long been a topic of interest for applications in various fields due to their special photoelectrochemical properties. However, there are some problems for practical applications of a pure TiO2 film. TiO2 can only be excited by ultraviolet light and its photoelectric conversion efficiency is low due to the high electron-hole recombination rate. In order to overcome these problems, many methods have been developed to modify TiO2 films for improving their photoelectrochemical properties.
In this work, we fabricated a Bi2S3 modified rutile TiO2 nanorod array film on FTO conductive glass for achieving a good photoelectrochemical cathodic protection effect on 403 stainless steel (403SS) in a NaCl solution.
A single crystalline rutile TiO2 nanorod array film was prepared by a typical hydrothermal reaction method. A FTO substrate (10 mm × 15 mm × 2.2 mm) was immersed in a TiCl4 solution and thermally treated in an electric oven at 70 ℃ for 30 min. After that, the FTO specimen was annealed at 550 ℃ in air for 1 h. Then the specimen with the TiO2 seed layer was immersed a mixed aqueous solution of TiCl4 and HCl, and heated in an electric oven at 150 ℃ for 10 h. Bi2S3 nanoparticles was prepared on the TiO2 ﬁlm by a typical chemical bath deposition method. The TiO2 ﬁlm sample was alternately immersed in the Bi(NO3)3 ethylene glycol solution and the Na2S aqueous solution for 1 min. After each immersion, the film sample was dried at 80 ℃ for 5 min. This operation cycle was repeated for 15 times. Finally, the film sample was annealed at 240 ℃ for 4 h in a N2 atmosphere.
The prepared films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and their photoelectrochemical properties and photocathodic protection effects were investigated.
The results indicated that the prepared TiO2 film was composed of the nanorod array. The TiO2 in the film was highly crystallized and agreed well with the rutile phase, and Bi2S3 nanoparticles were successfully deposited on the TiO2 film. The photoresponse of the Bi2S3/TiO2 composite film was extended into the visible light region, and its photoelectrochemical properties were enhanced. Under white light illumination, the Bi2S3/TiO2 composite film as a photoanode could make the potential of 403SS in a 0.5 M NaCl solution decrease by 695 mV (relative to its corrosion potential), showing a more effective photoelectrochemical cathodic protection effect than the pure rutile TiO2 nanorod film, which is of significance for environmentally friendly corrosion control of metals.
This work was supported by the National Natural Science Foundation of China (Nos. 21573182, and 21173177).
Kinetics of Pyrite Oxidation in Simulated Mine Tailings Pond Conditions
Authors: Nablo Geoffrey Ray Laviste 
Published: May 2020

Pyrite oxidation is the predominant source of acid mine drainage (AMD), which is one of the severe environmental impacts of mining. AMD destroys flora and fauna in the nearby ecosystem, and it causes grave health problems to the people. To further the understanding and help in the mitigation of AMD, this electrochemical study investigates the effect of the type and concentration of oxidant, and the presence of impurity (chalcopyrite) to the rate of pyrite oxidation, while simulating the conditions in tailings ponds.
Open Cell Potential (OCP) and Electrochemical Impedance Spectroscopy (EIS) analysis were done using a three-electrode cell set-up, which is composed of a pyrite rotating disc electrode (RDE), mercury/mercurous sulfate reference electrode in saturated potassium sulfate, and a platinum counter electrode, with a sulfuric acid working electrolyte. Polarization resistance obtained after fitting an electrical circuit to the EIS data was related to the rate of pyrite oxidation, while OCP was used to describe its oxidation mechanism. It was found out that the oxidation of pyrite by ferric ions preferentially occurred rather than by dissolved oxygen. The parameter setting with the lowest relative oxidation rate were: electrolyte with no ferric addition, and with nitrogen purging; and RDE with 10 % chalcopyrite addition. Reaction orders calculated for the effect of ferric ions and dissolved oxygen were equal to 1; but ferric has a higher slope value in the plot. Presence of chalcopyrite in the RDE caused the preferential oxidation of chalcopyrite instead of the pyrite due to their galvanic interaction. To minimize pyrite oxidation, ferric and dissolved oxygen concentration should be minimized, and chalcopyrite impurities should be increased.

Keywords: Electrochemical Impedance Spectroscopy, Acid Mine Drainage, Kinetics, Rotating-Disc Electrode, Pyrite
Addition of Functionalized Graphene Oxide in Smart Cataphoretic Coating
Authors: Rossi Stefano , Calovi Massimo , Benedetti Luca , Deflorian Flavio , Dirè Sandra , Ceccato Riccardo 
Published: May 2020

Graphene is a particular type of material, made of a single crystal lattice layer of two dimensional honey-comb structure with excellent electrical, thermal and mechanical properties.
Graphene oxide (GO) has been subjected to several studies in recent years. One of its possible applications concerns the production of composite coatings, to improve the protective properties of the coating itself together with other functional properties such as a remarkable conductivity.
The cataphoretic electrodeposition process allows to obtain a coating with uniform thickness also with complex geometry, good adhesion properties, in a simple and economic way. To get good properties it is important to have a uniform distribution of graphene flakes, avoiding cluster formation, together with good adhesion between graphene particles and organic matrix.
In this work, the effect of the graphene flakes addition in the organic coating was studied.
The graphene flakes have been subjected to nitric acid oxidation treatment and functionalized with organosilane, to get a good dispersion in the acrylic cataphoretic bath.
The deposits’ morphology was observed under optical and electronic microscope, to study the possible defectiveness of the coatings. The corrosion protection properties were evaluated by salt spray exposure test following the ASTM B117 standard and by electrochemical impedance spectroscopy measurements in chloride solution. The process parameters, as well as the concentration of functionalized graphene oxide inside the cataphoretic bath, have been optimized, obtaining composite coatings with excellent corrosion resistance properties. It has been verified that the presence of graphene in the cataphoretic coating allows to obtain a better behavior in an aggressive environment and corrosion protection of the metallic substrate. Finally, deposit conductivity was measured following ASTM D 257-07 standard.
Printing –Based Manufacturing of Flexible Ferroelectric Devices for Energy Harvesting Applications
Authors: Sundriyal Poonam , Bhattacharya Shantanu 
Published: May 2020

Flexible ferroelectric devices have attracted enormous interest in recent years due to their excellent energy harvesting performance.[1, 2] Most of the existing ferroelectric devices have rigid nature and therefore are incompetent for flexible/ wearable electronic applications.[3] Here, we report a flexible ferroelectric device developed by printing the ferroelectric device components on flexible substrates. The 3- D structures of graphene oxide (GO) and poly(vinylidene fluoride- trifluroethylene) [PVDF- TFE] were printed with different designs and configurations to develop an optimum device. The thickness of the printing layers and size of the components were optimized to achieve better device performance. This device exhibits excellent energy harvesting performance with outstanding device flexibility. The better performance of the hybrid material may be due to the high mechanical strength, excellent Young’s modulus, and high dielectric constant of GO. This study suggests the new manufacturing methods and better device design for further development of piezoelectric energy harvesting devices.
References:
1. Chen, X., X. Han, and Q.D. Shen, PVDF‐Based Ferroelectric Polymers in Modern Flexible Electronics. Advanced Electronic Materials, 2017. 3(5): p. 1600460.
2. Bhavanasi, V., et al., Enhanced piezoelectric energy harvesting performance of flexible PVDF-TrFE bilayer films with graphene oxide. ACS applied materials & interfaces, 2015. 8(1): p. 521-529.
3. Dagdeviren, C., et al., Recent progress in flexible and stretchable piezoelectric devices for mechanical energy harvesting, sensing and actuation. Extreme mechanics letters, 2016. 9: p. 269-281.
(Invited) Reliability and Scaling Perspectives of HfO2-Based OxRAM
Authors: Cagli Carlo , Sandrini Jury , Sassine Gilbert , Robayo Diego , Hammad Ismail , Molas Gabriel , Gaillard Fred 
Published: May 2020

Hafnium oxide OxRAM (Oxide Random Access Memory) is a non-volatile memory technology that has been widely investigated over the last 15 years. Its working mechanism relies on the formation and rupture of a tiny conductive filament through a HfO2 layer sandwiched between an active (Ti) and inert (TiN) electrodes. This causes the electrical resistance to very over three orders of magnitudes between a low resistance state (LRS) and a high resistance state (HRS).
OxRAM is a strong candidate to replace embedded Flash technology at scaled nodes. This is justified by several considerations but mainly driven by the low cost of integration and very high compatibility with standard CMOS technology. Yet OxRAM faces tremendous challenges in terms of reliability, variability and scaling.
In this paper we first show our latest findings in terms of reliability on a Ti/HfO2(5nm)/TiN cell. Controlling LRS and HRS resistance distributions can be achieved with a proper write/erase algorithm design (see Fig. 1) and it is a key point to enable large array integration. A proper write/erase sequence ensures long bit endurance up to 107 cycles. Data retention is then evaluated at four different temperatures (125, 165, 200 and 260 °C) to extract a 10 years retention temperature of 85°C.
Next, we discuss OxRAM scaling perspectives. In this context, it is essential to take into account both the resistive cell and its selector (most typically a MOS transistor). As recently shown [2], so far the OxRAM scaling has been mainly limited by the programming current, which determines the MOS selector size. Even if the OxRAM cell is integrated in the BEOL above its selector, the bitcell size is mostly determined by the underlying transistor. In addition, the OxRAM programming voltage dictates the transistor EOT and challenges the transistor reliability for scaled nodes. We demonstrated our OxRAM cell integration with a thin gate oxide FDSOI transistor (GO1/SG) and we show how this paves the OxRAM integration in a 28nm node.
Eventually we discuss the ultimate scaling perspective of an OxRAM array in a Cross-Point architecture. To enable such architecture the development of a BEOL selector is mandatory and we focused on Ovonic Threshold Switching device (OTS) for this scope. The OTS works switching between a low-conductive state and a metastable conductive one, which is voltage-triggered. We demonstrated (see Fig. 3) a 1S1R (one selector one resistor) OxRAM cell where the HfO2 memory is co-integrated with a series Ge-Sb-Se-N (GSSN) OTS. We eventually discuss the limits of this architecture showing that a trade-off exists between the half pitch of the Cross-Point array metal lines and the size of the memory bank.
REFERENCE
[1] G. Sassine et al., 2018 IEEE International Reliability Physics Symposium (IRPS).

[2] J. Sandrini et al., 2019 IEEE Electronic Device Meeting (IEDM).

[3] D. Alfaro Robayo et al., 2019 IEEE 11th International Memory Workshop (IMW).

Figure 1