bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conductivity Enhancement of Li2S Positive Electrode for All-Solid-State Rechargeable Lithium Batteries
Authors: Tatsumisago Masahiro , Hakari Takashi , Hayashi Akitoshi 
Published: February 2020

All-solid-state Li/S batteries with inorganic solid electrolytes have been studied because of their advantages of large energy density, good reversibility, and low cost. Preparation of sulfur composite electrodes using solid electrolyte and carbon additives is important for enhancing the utilization of sulfur and Li2S as an active material [1,2]. However, increasing sulfur or Li2S content in the composite electrodes tends to decrease reversible capacity because of their insulating nature. A melt diffusion process of sulfur into carbon pores is widely used for forming good sulfur-carbon contacts and inhibiting dissolution of polysulfide moieties into liquid electrolytes. We have prepared sulfur composite electrodes including 50 wt% sulfur by mechanical milling at 155oC, which is over the melting point of sulfur, and all-solid-state Li/S cells with the composite electrode showed the reversible capacity of over 1000 mAh g-1 at room temperature [3]. Alternative strategy to increase utilization of active materials is enhancing their lithium ion conductivity. Partial replacement of sulfide anions (S2-) in crystalline Li2S with iodide anions (I-) introduces lithium defects to Li2S and increases its lattice constant, and the structural modification will bring about conductivity enhancement.
In this study, we have prepared Li2S-LiI solid solutions by mechanical milling [4]. The starting materials of crystalline Li2S and LiI were milled using a planetary ball mill apparatus. X-ray diffraction (XRD) for the (100-x)Li2S∙xLiI (mol%, 0 ≤ x ≤ 20) milled samples indicated that XRD peaks attributable to crystalline LiI disappeared and those attributable to Li2S shifted to the lower angle side with an increase in the LiI content. The lattice constant of Li2S increased with an increase in the LiI content, suggesting that solid solutions in the system Li2S-LiI were prepared by mechanical milling. The solid solution at the composition of x = 20 showed the highest Li+ ion conductivity of 2.2×10-6 S cm-1, which is two orders of magnitude higher than that of Li2S. An all-solid-state cell (Li-In/Li3PS4/Li2S-LiI) operated as a rechargeable battery at room temperature. The cell with the x=20 solid solution as an active material exhibited a stable reversible capacity of 930 mAh per gram of Li2S (80% utilization) for 50 cycles at 0.07C. Further conductivity enhancement was achieved in the ternary system Li2S-LiI-LiBr, and the highest conductivity was over 10-5 S cm-1at the composition with 40 mol% lithium halides. The concept of increasing ionic conductivity of sulfur-based active materials is effective in increasing their utilization and reversible capacity for Li/S cells.

Acknowledgement

This research was financially supported by ALCA-SPRING project.

References

[1] M. Nagao et al., Electrochim. Acta, 56(2011) 6055.
[2] M. Nagao et al., J. Mater. Chem., 22(2012) 10015.
[3] M. Nagao et al., Energy Technol., 1(2013) 186. .
[4] T. Hakari et al., Chem. Lett., 44 (2015) 1664.
A Study of Surrogate Li-Ion Cell Fabrication and Characterization for Electric Vehicle Applications
Authors: Kwon OuJung , Miller Ted J. , Drews Andy , Yang Xiao Guang 
Published: February 2020

Ford has invested $2.1 million to open a new joint Li-ion battery fabrication and characterization laboratory at the Univeristy of Michigan. This prototyping laboratory enables multiple scale cell manufacturing and high process quality that is feasible to scale up, and evaluation of battery chemistries and electrode design while reducing the risk and cost. State-of-the-art manufacturing methods will be used to build surrogate cells that replicate the performance of full-scale production batteries, allowing for faster implementation in future production electrified vehicles. More details will be presented at the meeting.
Influence of Synthesis, Dopants and Cycling Conditions on the Cycling Stability of Lithium Nickel Manganese Oxyfluoride Spinels
Authors: Höweling Andres , Geßwein Holger , Binder Joachim R. 
Published: February 2020

Higher capacities and energies are needed in order to achieve widespread acceptance of Li-ion batteries as power sources in electric vehicles. In principle, Li-ion batteries offer two possibilities to achieve higher specific energies. Since the batteries’ energy is determined by the operational voltage and the active materials capacity, one could improve either the capacity of the active materials or the operating voltage of the cell.
Both approaches are pursued by many research groups. Higher capacities can for example be achieved with Li-rich layered oxides, where the use of more than 1 Li in the active material can considerably improve the capacity. The operational voltage is mainly determined by the potential of the cathode material vs. Li-metal. Therefore high voltage cathode materials
(e.g. LiMxMn2-xO4, with M = e.g. Ni, Co) are used.
However both approaches suffer from different limitations and problems. The need for balancing and the commonly relatively low mean voltages of ca. 3.5 V vs. Li+/Li0
reduce the gain in specific energy for materials with high capacities. On the other hand, the use of high voltage materials leads to unwanted site reactions and severe capacity fade when applied with a graphitic Anode. This is because the cells are operated above the stability window (ca. 1.0 – 4.3 V vs. Li+/Li0 in the presence of transition metal ions like Ni4+ and Mn4+) of current organic electrolytes. Furthermore the theoretical capacity of 147 mAh g-1 for the LiNi0.5Mn1.5O4 high voltage spinel is relatively low.
The shortcomings of the high voltage spinel can be overcome, when metallic lithium is used as the anode material. Not only the cycling stability is significantly improved but also the use of metallic lithium leads to the ability of cycling of 2 Li eq. per cycle, since the spinel lattice is able to host 2 Li eq. This is leading to a theoretical capacity of 294 mAh g-1 and therefore a theoretical specific energy of ~1030 Wh kg-1 can be reached when the cell is cycled between 2.0 and 5.0 V vs. Li+/Li0.
Unfortunately, the cycling of 2 Li eq. is leading to a severe capacity fade due to a phase transition from cubic to tetragonal in the low voltage region associated with material degradation.
In this work doping with transition metal ions is used to improve capacity retention when cycling between 2.0 and 5.0 V vs Li+/Li0. Initial capacities and stabilities are directly dependent on synthesis conditions and doping elements. The goal is to achieve a high stability of the material at a low tradeoff of capacity. Therefore different combinations of doping elements are used and tested at different cycling conditions. In addition to the transition metal ions, fluorine doping is also used to increase cycling stability.
The influence of different synthesis, doping and cycling conditions on cycling stability and capacity retention are discussed.
Improved Adhesion and Electrochemical Properties of Silicon/Carbon Composite Anodes By Using a Co-Polyimide Binder
Authors: Kim Kyuman , Choi Jaecheol , Cho Kuk Young , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

Silicon (Si) is a promising anode candidates due to high theoretical capacity of 3500 mAh g-1, which is approximately 10 times higher than the capacity of conventional graphite anodes. However, Si anodes have not been widely introduced into commercial lithium-ion batteries (LIBs), because they experience large volume expansion (~400%) during charge-discharge cycling. In order to alleviate this expansion during Li+insertion and extraction, the choice of binder for holding all of the components in the Si anode is very important. Although polyvinylidene fluoride (PVdF) has been widely utilized as a polymeric binder for commercialized LIBs over decades, lots of previous works have proved that PVdF could not provide the Si anodes with sufficient physical property to keep their original anode structure. To overcome the limitation of PVdF, a number of researchers have proposed new polymeric binder such as polyacrylic acid (PAA) [1], alginate [2] and polyimide (PI).[3-4] However, there is no LIBs adopting the only Si for their anode due to small but continuous electrolyte decomposition and pulverization for a long cycle life.
Herein, we fabricate silicon/carbon (Si/C) composite anodes with highly adhesive and soluble co-polyimide (P84) binder. Their adhesion and electrochemical properties are evaluated by comparing conventional PVdF binder system. In addition, the loading level and density of electrodes are also changed to find an optimum binder contents or design parameters.

Acknowledgements

This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977).

References

[1] Magasinski, A.; Zdyrko, B.; Kovalenko, I.; Hertzberg, B.; Burtovyy, R.; Huebner, C. F.; Fuller, T. F.; Luzinov, I.; Yushin, G., Toward Efficient Binders for Li-Ion Battery Si-Based Anodes: Polyacrylic acid. ACS Appl. Mater. Interfaces 2010, 2, 3004-3010.
[2] Ryou, M. H.; Kim, J.; Lee, I.; Kim, S.; Jeong, Y. K.; Hong, S.; Ryu, J. H.; Kim, T. S.; Park, J. K.; Lee, H., Mussel‐Inspired Adhesive Binders for High‐Performance Silicon Nanoparticle Anodes in Lithium‐Ion Batteries. Adv. Mater. 2013, 25, 1571-1576.
[3] Choi, J.; Ryou, M.-H.; Son, B.; Song, J.; Park, J.-K.; Cho, K. Y.; Lee, Y. M., Improved High-Temperature Performance of Lithium-Ion Batteries through Use of a Thermally Stable Co-Polyimide-Based Cathode Binder. J. Power Sources 2014, 252, 138-143.
[4] Choi, J.; Kim, K.; Jeong, J.; Cho, K. Y.; Ryou, M.-H.; Lee, Y. M., Highly Adhesive and Soluble Copolyimide Binder: Improving the Long-Term Cycle Life of Silicon Anodes in Lithium-Ion Batteries. Appl. Mater. Interfaces 2015, 7, 14851-14858.

Figure 1
Reduction of Charge and Discharge Polarization By Cobalt Nanoparticles-Embedded Carbon Nanofibers for Lithium-Oxygen Batteries
Authors: Kim Yun-Jung , Lee Hongkyung , Lee Dong Jin , Noh Hyungjun , Lee Jinhong , Park Jung-Ki , Kim Hee-Tak 
Published: February 2020

The battery material community has a persistent consensus that Li–O2 batteries would be the most promising next generation batteries due to its extraordinarily high energy densities; from a practical view point, at least 2~3 times higher than those of conventional lithium ion batteries (LIBs).[1] However, Li–O2 batteries suffer from their chronically low round trip efficiency due to poor reversibility of lithium peroxide, Li2O2, which is main product of discharged Li–O2 batteries. This truly originates from its intrinsically poor electron and ionic conductivity.[2] Therefore, the reduction of charging overpotential is in urgent need for economical progress of Li–O2 batteries.
In an effort to achieve high round trip efficiency, recent studies have attracted great attention that the charge behaviors of Li–O2 cells can be manipulated by controlling the phase structure and morphology of Li2O2 formed during discharge. In particular, at a low current density, the large toroidal structured, crystalline Li2O2 was primarily formed. In contrast, the formation of film-like amorphous Li2O2 is favored at high current density. [3,4] Owing to its structural advantages of enhanced ionic and electronic transport[5], the oxidation of less crystalline Li2O2 is more efficient, resulting in significant decrease on charge overpotential. Consequently, the controlling phase and morphology of Li2O2 is an effective strategy for manipulating charge behavior of Li–O2 cells.
As a possible approach for controlling Li2O2, we designed an effective electrochemical catalyst of oxygen reduction reactions in Li-O2 batteries, a cobalt nanoparticles (Co NPs) embedded carbon nanofibers (Co-CNFs). As a result, embedded Co NPs leads to the formation of uniform film-like amorphous Li2O2, and thus, the Li–O2 battery employing the Co-CNF provides a round trip efficiency of > 77% and extends cycling stability by more than 6 times in comparison with a CNF electrode. These change of Li2O2 mainly is derived from a charge delocalization originating from the electron transfer from Co NPs to C-atoms. According to HSAB theory, highly concentrated Li+ ions near electrode resulting from the preferable interaction with Co-CNFs could lead to the rapid precipitation of Li2O2 and prevent the crystallization of Li2O2. The findings suggest a novel electrode design strategy of combining inexpensive metal and carbons for modulating the phase of discharge product.

References

[1] Nat. Mater. 2012, 11, 19-29
[2] J. Phys. Chem. Lett. 2013, 4, 93−99
[3] J. Am. Chem. Soc, 2013, 135, 15364−15372
[4] Energy Environ. Sci., 2013, 6, 1772
[5] Chem. Mater, 2014, 26, 2952−2959
In Situ and Ex Situ NMR Studies of High-V Li Cathode Materials
Authors: Hu Yan-Yan , Feng Xuyong , Li Xiang , Chien Po-Hsiu , Rose Alyssa 
Published: February 2020

Developing high-capacity, high-power, and low-cost cathodes for PHEV and EVs has been an important endeavor in recent years. Lithium- and Manganese-rich cathodes have attracted major research and development efforts. Major obstacles to address include structure (both surface and bulk) stabilization, hysteresis, and voltage fade. Our research effort in this area focuses on understanding the fundamental chemistry related to those obstacles and designing mitigation strategies to improve the performance of high-V cathodes for rechargeable LIBs.
Solid-state NMR has its unique advantages over other techniques in investigating functional light elements (e.g., Li, Na, H, O). In particular, in situ NMR is capable of catching transient processes. In situ
7Li NMR was employed to monitor the intercalation and de-intercalation of Li in important rechargeable battery systems and to help illustrate the effects of ion migration on the bulk and surface structures. The new in situ NMR probehead design provides convenient connections to battery electrodes, cancellation of noise pickup, and a variable temperature range of -50-100oC, which is helpful to evaluate the temperature-dependence of the battery performance. Ex situ
17O MAS NMR experiments have also been employed for the first time to directly probe O migration and loss over extended cycling. Chemical surface modifications, bulk composition variation, and new synthesis methods have been applied to improve battery performance.

Figure 1
Improved Corrosion Resistance of AA2024 Alloys through Hybrid Organic-Inorganic Sol-Gel Films Modified with Piperazine
Authors: Jiménez-Morales Antonia , Carbonell Diogenes , Montoya Rodrigo , Gelling Victoria J. , Galvan Juan Carlos 
Published: February 2020

Hybrid sol-gel coatings were prepared by using mixtures of γ-methacryloxypropyltrimethoxysilane (MAPTMS) and tetramethylorthosilicate (TMOS) as organopolysiloxane precursors and piperazine as a corrosion inhibitor [1]. The sol-gel films were characterized by using Fourier transform infrared spectroscopy (FTIR), liquid state Si liquid-state nuclear magnetic resonance spectroscopy (29Si NMR) and viscosity measurements. The corrosion performance of the resulting coatings was analysed by using Global and Local Electrochemical Impedance Spectroscopies (EIS, LEIS). The study shows that these new coatings have promising anticorrosive properties when they are used for the corrosion protection of AA2024-T3 alloys in contact with NaCl aqueous solution.
The incorporation of piperazine additionally results in more effective barrier proprieties and improved corrosion protection of AA2024-T3 alloys acting firstly as a catalyst for Si-OH condensation during the polymerization of the organopolysiloxane network increasing film thickness and secondly as a metal corrosion inhibitor of the metal substrate in the base of pores of the sol-gel film.
Acknowledges:
This work was supported by the Ministry of Economy and Competitiveness of Spain (Project MAT2015-65445-C2-1-R) and Comunidad de Madrid (Project S2013/MIT-2862-MULTIMAT-CHALLENGE).
References
D.J. Carbonell, A. García-Casas, J. Izquierdo, R.M. Souto, J.C., Galván, A. Jiménez-Morales, Scanning electrochemical microscopy characterization of sol-gel coatings applied on AA2024 substrate for corrosion protection, Corrosion Science, 111 (2016) 625–636.
Corrosion Protection of Internal Surface of Natural Gas Transmission Line By Metallic Coating
Authors: Tylczak Joseph H , Rodriguez Alvaro , Ziomek-Moroz Margaret 
Published: February 2020

Natural gas transmission pipelines are a known to leak and thus release methane which is a greenhouse gas (GHG). There are several mechanisms for these emissions, including venting of lines, mechanical damage, and corrosion failure. With the projected pipeline life being described as “virtually forever”, slow corrosive attack can be an issue. The corrosive failure can be by either the exterior or interior attack. While there are practices in place to protect the exterior of the pipelines, including organic coatings and impressed cathodic protection, these techniques are not practical for the pipe’s interior. While dry natural gas is considered non-corrosive, the maintenance/inspect process of pigging of pipelines typicality results in black corrosion deposits being removed. These corrosion deposits are most likely a result of inadvertent water reacting with residual carbon dioxide (CO2) forming carbonic acid and attacking the pipeline, particularly wherever this water pools.
This research examined the use of sacrificial coatings on the interior of natural gas pipelines to protect the pipeline from corrosion. These tests simulated the case where trapped water is in the bottom of the pipeline. A typical natural gas pipeline can have 100 bar of pressure. The gas stream can have 3 to 4 vol % CO2. This can result in a CO2 partial pressure of 3 to 4 bars. NACE SP0106 says that CO2 at a partial pressure of greater than 2.1 bar in the presence of water is usually corrosive. Compression of the gas, which occurs every 40 to 100 miles, heats the gas which will accelerate the corrosion rate. The work examined the corrosion of an API 5L grade X65 steel in a test, 3 ½ wt. pct. NaCl solution with a 3.1 bar pressure of CO2 at 40 °C. Results of the corrosion rate of the bare steel were compared with that of several sacrificial metals, including Al and Zn. The corrosion rate of the steel coupled to sacrificial metals was measure for both parts of the couple.
Investigation of Corrosion Resistance for Annealed and Hardened Stainless Steels
Authors: Repukaiti Reyixiati , Fast Cody , Murkute Pratik , Tucker Julie , Isgor Burkan 
Published: February 2020

Stainless steels are desirable for their good corrosion resistance and mechanical properties and are widely used in seawater exposure conditions that require high hardness. Heat treatment procedures to increase the hardness of stainless steel affect microstructural, compositional and surface properties of these materials, hence affect their corrosion resistance. To investigate this relationship a series of corrosion resistance and mechanical tests in room temperature and ambient pressure has been conducted for stainless steels (duplex 2101, duplex 2205, 17-4, 17-7, 15-5, 316, AL-6XN, Inconel600, ATI800, ATI347, 420) that are exposed to simulated seawater conditions to evaluate them in annealed and hardened conditions.
Preliminary salt solution spray tests have indicated that duplex stainless steel 2205, stainless steel 17-7, and stainless steel 15-5 have better corrosion resistance than other alloys in annealed condition. A series of electrochemical impedance and cyclic potentiodynamic polarization measurements were conduced for duplex stainless steel 2205, stainless steel 17-7, and stainless steel 15-5 in order to evaluate their corrosion resistance both in annealed and hardened conditions. Mechanical tests include micro hardness tests on annealed and hardened alloys, and charpy impact tests on hardened alloys. It was shown that the final selection of materials was primarily controlled by their corrosion resistance, as the mechanical properties of the alloys show only slight variation. The mechanisms that lead to changes in corrosion resistance due to heat treatment processes are discussed.
Biogas Upgrading in a 50 Kilowatt Solid Oxide Cells Based Demonstration Plant - Design and Operational Experiences Including Strategies to Counteract Degradation
Authors: Hansen John Bøgild 
Published: February 2020

There are considerable incentives to use intermittent electricity generation for production of stporable energy carriers. Upgrading biogas to pipeline quality gas by methanation of the CO2 content in the biogas with hydrogen from electrolysis is one option.
Solid Oxide electrolysis (SOEC) offer strong synergy with the methanation plant, as the steam produced by the exothermal methanation reaction can be used directly as feedstock for the SOEC thus eliminating water evaporation by electricity.
A pilot plant to demonstrate the concept has been constructed and was operational mid 2016. The design capacity is 10 Nm3/h of upgraded biogas. This capacity requires approx. 50 kW SOEC, which is provided by two Fuel Cores, each consisting of 4 SOEC stacks. Haldor Topsøe A/S has also designed the biogas cleaning unit and the methantion plant which is located at the Agricultural Research Centre of Aarhus University at Foulum, Jutland.
The paper will outline the design of the pilot as well as full scale plants including exergy analyses. Experimental data from the SOEC unit(s) as well as the biogas cleanup and methanation pilot will be presented.

Figure 1
Electrochemical Reduction of CO2 Using Cu-Au Nanoparticles: Effects of Size and Composition
Authors: Andrews Evan Michael , Flake John , Fang Yuxin 
Published: February 2020

The electrochemical reduction of CO2 to light hydrocarbons allows renewable energy storage without increasing net atmospheric CO2. Alloys and nanoscale catalysts have emerged as potential electrocatalysts with high efficiencies and selectivities to valuable products. Here, we describe CuAu alloy nanoclusters with diameters of 2 nm and 5 nm for use as CO2 electroreduction catalysts. The Cu:Au ratio was controlled to yield nanoparticles with a range of alloy compositions ranging from Cu25Au75 to Cu72Au28. The yields and onset potentials were measured and compared to Cu, Au and CuAu bulk foils, where the nanoparticles showed a 50 fold increase in CO yield compared to Au foil, and greater than a 100 mV anodic shift in CO2 reduction onset potentials. As seen in Figure 1, the alloys showed greater improvements in yield as Au content increased. These improvements are attributed to low coordination active sites and to the bimetallic nature of these active sites.

Figure 1