bluuebunny/crossref_metadata_2025 huggingface dataset:
Durability and Reliability of EV Batteries Under Electric Utility Grid Operations Bidirectional Charging Impact Analysis
Authors: Devie Arnaud , Baure George , Dubarry Matthieu
Published: February 2020

Vehicle-to-grid (V2G) and grid-to-vehicle (G2V) strategies are often cited as promising approaches to mitigate the intermittency of renewable energy on electric power grids. However, their impact on the vehicle battery degradation has not been investigated in detail.

The aim of this work was to understand the impact of bidirectional charging on commercial Li-ion cells used in electric vehicles today. The influence of V2G and G2V strategies and calendar aging on capacity loss, resistance increase, and rate capability for commercial graphite / LiNixCo1-x-yAlyO2batteries were studied.

Results showed that additional cycling to discharge vehicle batteries to the power grid, even at constant power, was detrimental to cell performance. A V2G step once a day was found to accelerate the capacity loss by 33% and the resistance increase by 5%. This step twice a day increased the capacity loss by 75% and the resistance by 10%. In contrast, delaying the charge (G2V) over immediate charging had no significant effect (< 1%) on the capacity retention and a limited impact on the resistance (< 5%) at room temperature. Charging twice per day resulted in 5% less capacity loss and similar resistance increase compared to charging just once daily. In the calendar aging experiments, the capacity loss as a function of time, SOC, and temperature was modeled using a quadratic equation. Of the factors investigated, storage temperature was found to have the biggest impact on capacity loss and rate capability; while, the SOC had the most deleterious effect on the resistance.

Our study concluded that EVs using similar cells should not be left fully charged in warmer climates. Moreover, predictions based on the measurements indicated that V2G implementation would decrease the lifetime of the battery packs below 5 years. The impact of delaying the charge in order to reduce the impact on the power grid, was found to be negligible at room temperature, but could be significant in warmer climates.
(Battery Division Research Award Address) Developments of New Ionic Conductors and Their Application to All-Solid-State Batteries
Authors: Kanno Ryoji
Published: February 2020

All-solid-state is an ideal form of battery. The all-solid-state battery offers an attractive option owing to their potential in improving the safety and achieving both high power and high energy densities. Despite extensive research efforts, the development of all-solid-state batteries still falls short of expectation largely because of the lack of suitable candidate materials for the electrolyte required for practical applications. Among the electrolytes proposed, the sulphide system is a candidate because of its high ionic conductivity1). The Li10GeP2S12 (LGPS) exhibits high bulk conductivity of over 10-
2 S cm-1 at room temperature and is promising for applications requiring batteries with high power and energy densities2). On the other hand, material variations may provide suitable combinations of the electrodes and the electrolyte. Specifically, new LGPS-type superionic conductors exhibit extremely high conductivity (25 mS cm-1, Li-Si-P-S-Cl system) and high stability (~0 V vs Li metal, Li-P-S system), which enable the generation of high power and ultrafast charging of all-solid-state cells with high energy densities3). The present study reviews the materials varieties and the materials design concepts of the solid electrolytes with the LGPS-type structures. The effects of conductivities and electrochemical stabilities of the electrolytes on the battery characteristics will be discussed.

References

1) R. Kanno, et al., J. Electrochem. Soc., 148, (7), A742-A746 (2001).

2) N. Kamaya, et al., A. Mitsui, Nature Materials, 10, 682 (2011).

3) Y. Kato, et al., Nature Energy, 1, 201630, (2016).
(Battery Division Postdoctoral Associate Research Award Address, sponsored by MTI Corporation and the Jiang Family Foundation) The Solvation Structure of Active Cations in Next-Generation Battery Electrolytes
Authors: See Kimberly A , Gewirth Andrew A
Published: February 2020

Next-generation batteries offer the promise of higher performance using materials that are less expensive and more abundant than those in convention Li-ion cells. From a fundamental point-of-view, the new chemistries involved in these also systems allow for exploration of the unknown and generation of new, fundamental knowledge. To that end, this talk will explore the local structure of the active cations in electrolyte solutions for Li-S and Mg batteries and the effect of this structure on the charge storage reactions and ultimately on the battery metrics.

The first part of the talk will discuss the emerging solvate electrolytes as possible electrolyte solutions for Li-S batteries. The solvate electrolytes are characterized by extremely high quantities of salt resulting in interesting electrochemistry at the S cathode. Because the behavior of the electrolyte solution is governed by the complexes in the solution, we will explore the local solvation structure of the active cation, Li+, and how it is affected by the addition of what are commonly thought to be innocuous cosolvents. The addition of the cosolvents to the solvate electrolyte results in subtle but important changes in the Li+ solvation structure that affect the kinetics of the S reduction.

The second part of the talk will focus on electrolytes for Mg batteries. We will explore the local structure of Mg2+ in the seemingly simple MgCl2 + AlCl3 in THF electrolyte known as the magnesium aluminum chloride complex (MACC) electrolyte. The importance of Mg speciation in active electrolytes and the effect these complexes have on the charge transfer processes at the electrode-electrolyte interface will be addressed. We will also explore the role of chloride in facilitating the electrodeposition of divalent Mg2+ and the implications of using halogenated electrolytes in full cells.

Figure 1
Primary Batteries for Emerging Deep Space Exploration Missions
Authors: Brandon Erik J. , Billings Keith J. , Ratnakumar Bugga V. , Chin Keith B. , Jones John-Paul , Jones Simon C. , Krause Frederick C. , Ontiveros Raymond A. , Pasalic Jasmina , Smart Marshall C. , West William C.
Published: February 2020

Primary batteries have played a critical role in past deep space planetary exploration missions, providing power to spacecraft such as the Galileo and Huygens Probes [1,2]. Most of these missions were of relatively short duration (Huygens lasted 2.5 hours), and relied on primary battery power alone to execute mission profiles. Future missions planned by the National Aeronautics and Space Administration (NASA) to the outer planets (Jupiter, Saturn) and their moons (Europa, Enceladus, Titan) will require more advanced primary batteries to provide bus power for days or even weeks. These batteries may be stored for several years during an initial cruise period, followed by operation in temperature extremes coupled with exposure to high radiation doses.

The requirement for primary batteries with very high specific energy, low self-discharge/long calendar life performance, wide temperature operation and radiation tolerance has prompted the evaluation by NASA of commercially available options, as well as the development of new components and cell designs. This includes higher specific energy battery chemistries such as Li/CFx and Li/CFx-MnO2, which provide for a higher capacity per unit mass at moderate rates, relative to Li/SO2 and Li/SOCl2 chemistries used in previous missions. Current efforts to evaluate the effects of radiation and storage on these primary battery chemistries will be discussed in relation to future NASA needs.

ACKNOWLEDGEMENT

The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration (NASA).

L.M. Hofland, E.J. Stofel, R.K. Taenaka, Aerospace and Electronic Systems Magazine IEEE, 11, 14 (1996).

B.P. Dagarin, R.K. Taenaka, E.J. Stofel, Proc. of 31st Energy Conversion Engineering Conference 1996,
1, 427 (1996).
(Battery Division Postdoctoral Associate Research Award Address, sponsored by MTI Corporation and the Jiang Family Foundation) K-Ion Battery for a Next-Generation Energy Storage System
Authors: Kim Haegyeom , Kim Jae Chul , Seo Dong-Hwa , Bo Shou-Hang , Kwon Deok-Hwang , Shi Tan , Ceder Gerbrand
Published: February 2020

Li-ion batteries (LIBs) have succeeded in powering small portable electric devices and are currently expanding to large scale applications (i. e. electric vehicles and grid-level energy storage systems). However, it is still debatable whether Li reserves can meet the increasing demand on such emerging applications. In fact, cost performance becomes the most important factor in the large scale applications. In this respect, K-ion batteries (KIBs) and Na-ion batteries (NIBs) are considered alternative energy storage systems due to the natural abundance of K and Na reserves. KIB technology is particularly interesting because K has a lower standard redox potential than Na in non-aqueous carbonate-based electrolytes that are commonly used for NIBs,1-3 indicating that KIBs can potentially have a higher cell voltage than NIBs. More importantly, graphite, which has been used as a standard anode for LIBs because of low production cost as well as high density, can intercalate K ions reversibly while it cannot accommodate Na intercalation.3,4

To realize practical KIBs, it is of primary importance to develop novel positive electrodes. In this study, we develop new cathode materials with layered-structure (i. e. KxTMO2, TM = Co and Mn)5, 6 for KIBs and investigate K-storage properties and underlying K-storage mechanism in them by in-situ diffraction and electrochemical characterization combined with theoretical first-principles calculations.

References

1. Eftekhari, A. et al. Potassium Secondary Batteries. ACS Appl. Mater. Sci., 9, 4404. (2016).

2. Marcus, Y. Thermodynamic functions of transfer of single ions from water to non-aqueous and mixed solvents: Part 3 - Standard potentials of selected electrodes. Pure and Applied Chemistry 57, 1129. (1985).

3. Komaba, S. et al. Potassium intercalation into graphite to realize high-voltage/high-power potassium-ion batteries and potassium-ion capacitors. Electrochem. Commun. 60, 172. (2015).

4. Jian, Z., et al. Carbon Electrodes for K-Ion Batteries. J. Am. Chem. Soc. 137, 11566. (2015).

5. Kim, H. et al. K-Ion Batteries Based on a P2-Type K0.6CoO2 Cathode. Adv. Energy Mater. 1700098. (2017)

6. Kim, H. et al. Investigation of potassium storage in layered P3-type K0.5MnO2 cathode. Adv. Mater. Under revision. (2017)
Advancing Sodium-Based Batteries for Grid-Scale Energy Storage
Authors: Spoerke Erik D. , Small Leo J. , Lamb Joshua , Clem Paul , Ingersoll David , Bhavaraju Sai , Eccleston Alexis
Published: February 2020

Development of safe, low-cost, grid-scale electrical energy storage remains a national priority, critical to agile, reliable energy distribution, transformative renewable energy integration, effective emergency response, and even successful national defense initiatives. Viable candidate energy storage systems must be able to reliably provide the high capacity and power needed to meet evolving electrical demands while remaining cost-effective and safe. With current large scale battery technologies challenged by high cost, limited cyclability, and potentially hazardous runaway reaction behaviors, there is a clear need to develop alternative battery technologies. Here, I will describe a new generation of intermediate temperature molten sodium-based batteries, enabled by the solid state electrolyte NaSICON (Na Super Ion CONductor). NaSICON provides exceptional low-to-intermediate temperature sodium ion conductivity, exhibits excellent chemical and mechanical stability, and can be produced in a range of form factors on an industrial scale. Integrating molten sodium anodes, NaSICON solid state electrolytes, and AlCl3-based molten salt catholytes, we create high performance, all-inorganic battery constructs that operate below 200oC and avoid hazards associated with runaway exothermic reactions, polymer separators, and organic electrolytes used in other batteries. I will describe the design and scalable performance (up to 250Wh) of several emerging intermediate temperature molten salt technologies including Na-NiCl2 and Na-I2. These promising, intermediate temperature technologies boast coulombic efficiencies near 100% and energy efficiencies >80% through months of stable electrochemical cycling. Moreover, accelerated rate calorimetry verifies the inherent safety of these molten salt chemistries, revealing neither the runaway exothermic reactions nor hazardous pressurized gas generation that plague other large-scale battery systems. The encouraging performance of these intermediate temperature molten salt battery systems promises new opportunities to meet the need for reliable, safe, and cost-effective solutions to growing national challenges in grid-scale electrical energy storage.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Beyond Li-Ion Chemistry for High Energy Aqueous Battery
Authors: Yang Chongyin , Wang Chunsheng , Suo Liumin , Wang Fei
Published: February 2020

Leveraging the most recent success in expanding electrochemical stability window of aqueous electrolytes, we applyed a few new aqueous chemistries of both high energy density and safety. We show that in the super-concentrated aqueous electrolyte, these electrochemistry couples can exhibit high capasity and high voltage, which depend on thermodynamically phase-separations from the super-concentrated aqueous electrolyte. Meanwhile, fast reaction kinetics and negligible active material dissolution are also shown. The aqueous Li-ion/sulfur full cell delivers record-high energy densities up to 200 Wh/(kg of total electrode mass) for >1000 cycles at ~100% coulombic efficiency. The aqueous Li-ion/graphite full cell is heading the 300 Wh/kg target. These performances already approaches that of commercial LIBs using non-aqueous electrolyte, along with intrinsic safety not possessed by the latter. The excellent performance of this new aqueous battery chemistry significantly promotes the practical possibility of aqueous LIBs in large-format applications.
(Invited) Solid State Electrolytes for Beyond Lithium Ion Batteries
Authors: Thangadurai Venkataraman
Published: February 2020

At present, lithium batteries conquer much attention because of their widespread applications ranging from portable electronics to transportation and grid storage. The next-generation safe and robust lithium batteries require highly conducting solid electrolytes with excellent chemical stability with elemental Li and high voltage cathodes. Garnet-type metal oxides such as Li5La3Ta2O12, Li6La2BaTa2O12, and Li7La3Zr2O12 are promising candidates because of their high bulk ionic conductivity, low electronic conductivity and high electrochemical stability (up to 6V/Li).1-3 It is critical to understand the ion transport mechanism in these garnet-type oxides with respect to change in lithium content and temperature to further develop highly conducting practical solid electrolytes for next generation Li batteries. The present study reports effect of Y-doping for Ta in Li5La3Ta2O12 on structural, chemical, morphological and electrical properties. Analysis of crystal structure and electrical properties are performed using powder X-ray diffraction, NMR, and ac impedance spectroscopy to understand the Li ion migration pathways in Li5+2xLa3Ta2-xYxO12 (0.05 ≤ x ≤ 0.75).4,5 The x = 0.75 member of Li5+2xLa3Ta2-xYxO12 exhibits the highest conductivity of 10-4 Scm-1 at 23 ºC. In addition, high stability in aqueous solution makes Li5+2xLa3Ta2-xYxO12 suitable to use as Li protection layer in lithium-aqueous batteries.3
 

References

1.V.Thangadurai, H. Kaack, and W. Weppner, J. Am. Ceram. Soc.,
86, 437 (2003).

2. R. Murugan, V. Thangadurai and W. Weppner, Angewandte Chemie International Edition, 46, 7778 (2007).

3. V. Thangadurai, S. Narayanan, and D. Pinzaru, Chem. Soc. Rev.
43, 4714 (2014).

4. S. Narayanan, F. Ramezanipour, and V. Thangadurai, Inorg. Chem.
54, 6968 (2015).

5. A.K. Baral, S. Narayanan, F. Ramezanipour, and V. Thangadurai, Phys. Chem. Chem. Phys. 16
, 11356 (2014).
Metal Hydride–Oxide Paired Anode for All-Solid Li-Ion Batteries
Authors: El kharbachi Abdel , Uesato Hiroki , Yamaguchi Shotaro , Sørby Magnus Helgerud , Miyaoka Hiroki , Ichikawa Takayuki , Fjellvåg Helmer , Hauback Bjørn Christian
Published: February 2020

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

Acknowledgements

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

References

[1] Y. Oumellal, A. Rougier, G.A. Nazri, J.M. Tarascon, L. Aymard, Metal hydrides for lithium-ion batteries, Nat Mater, 7 (2008) 916-921.

[2] L. Zeng, K. Kawahito, S. Ikeda, T. Ichikawa, H. Miyaoka, Y. Kojima, Metal hydride-based materials towards high performance negative electrodes for all-solid-state lithium-ion batteries, Chem. Commun., 51 (2015) 9773-9776.

[3] P. Poizot, S. Laruelle, S. Grugeon, L. Dupont, J.M. Tarascon, Nano-sized transition-metal oxides as negative-electrode materials for lithium-ion batteries, Nature, 407 (2000) 496-499.
Engineered Porous Foam Electrodes - New Approaches to Dendrite-Free Anodes for Li-Metal Batteries
Authors: Jampani Hanumantha Prashanth , Day Brian Austin , Datta Moni Kanchan , Murugavel Shanthi Pavithra , Gattu Bharat , Kumta Prashant N
Published: February 2020

Dendrite formation is a well-known metallurgical phenomenon occurring as a result of several energy minimization processes including preferential growth during solidification or stress-related grain-boundary evolution(1, 2). The occurrence of dendritic structures in electrochemical cells however, occurs as a result of electrochemical stripping/plating steps involving nucleation and growth processes(3).

In this work, engineered porous foams are demonstrated as stable electrodes with high coulombic efficiency and limited orthogonal growth of surface dendrites. This unique approach is used to address dendritic growth and volumetric changes associated with plating/deplating of large volumetric amounts of lithium to generate thick lithium metal anodes. Figure 1 depicts the foam morphology as well as displays the superior performance of the new engineered electrodes over 100 cycles where almost no drop in coulombic efficiency is observed at very high current densities of ~100 mA/cm2. This presentation will examine the mechanisms associated with fabrication and design of such engineered porous foam electrodes resulting in the depicted noteworthy stable cycling.

Figure caption:

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

References

1. S.-C. Huang and M. Glicksman, Acta Metallurgica, 29, 701 (1981).

2. T. Okamoto and K. Kishitake, Journal of Crystal Growth, 29, 137 (1975).

3. A. Despic, J. Diggle and J. M. Bockris, Journal of The Electrochemical Society, 115, 507 (1968).

Figure 1
Elastic and Stretchable Gel Polymer Electrolyte Coating to Improve Long-Term Cycling Stability of High-Areal-Capacity Sio Electrode for Lithium-Ion Battery
Authors: Huang Qingquan , Song Jiangxuan , Gao Yue , Wang Donghai
Published: February 2020

Si-based anode is an advanced anode material to improve the energy density of Li-ion battery. In order to pair with commercial cathode, the areal capacity of Si-based anode should be increased to 3-4 mAh/cm2. However, high-areal-capacity Si-based anode still encounters fast capacity fading and poor cycling stability, because large volume change upon cycling will damage electrode structure integrity and arise accumulated growth of SEI (solid electrolyte interface) layer. Here we develop an elastic and stretchable polyurethane-urea (PUU) gel polymer electrolyte (GPE) coating strategy to improve the long-term cycling stability of high-areal-capacity SiO anode. The PUU polymer coating can swell and uptake 48 w% carbonate electrolyte, providing a moderate ionic conductivity of 2.4*10-4 S/cm at room temperature. The GPE shows good chemical and electrochemical stability with lithium metal. At the electrode level, the GPE coating can improve electrode adhesion strength and alleviate electrode thickness change during charge/discharge process. For long-term cycling, the GPE coating can restrict the pulverized particles in a localized space to prevent loss of conductive network and maintain the electrode structure integrity. In the half-cell test, the SiO electrode with GPE coating shows a reversible capacity of 3.0 mAh/cm2 (or specific capacity of 1200 mAh/g) for 280 cycles. In the full-cell test, the cell of pre-cycled NCM/pre-cycled SiO electrode with GPE coating has a reversible capacity of 2.1 mAh/cm2 (or specific capacity of 150 mAh/g) for 200 cycles, with an improved Coulombic efficiency of 99.9%.
Orientation Effects of Electrode with Various Wettability on Deep Discharge Capacity of Li-O2 Batteries
Authors: Wang Fangzhou , Li Xianglin
Published: February 2020

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

Energy storage technology is attracting more attention with world-wide increase of renewable energy deployment, such as solar and wind power. With energy storage, electrical energy from photovoltaic cells or wind turbines can be stored when production exceeds consumption and back to the grid when load is demanded. The energy storage devices can also serve as a part of distributed power generation system for remote islands or uninterruptible power supply applications. Usually the system is installed in rural areas and even subjected to harsh temperatures and punishing humidity. Therefore, reliable and efficient energy storage is required. However, most existing mature energy storage technologies, such as Ni-Cd, Ni-MH and Li-ion, can barely satisfy both issues of safety and low cost. Metal air batteries have high theoretical specific energy density, being capable of fulfilling multiple needs for the next generation of mobile/stationary energy storage system. They are also environmentally benign, and inexpensive; frequently used metal anodes including Al, Zn, and Fe are naturally abundant. However, an air electrode with the capability of possessing both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) efficiently is still not well developed at the moment. In the present work, the bifunctional air electrode composed of alpha phase of manganese oxides or silver particles, as ORR catalysts, grown on the surface of stainless steel mesh catalyzing OER, was fabricated via electro-deposition method. This as-synthesized oxygen electrode was used directly for zinc-air battery assembly without polymer binders, which have low conductivity and suffer from detaching when immersion in alkaline solutions, leading to battery failure and short cycle life. In our system, the zinc-air battery was assembled with as-synthesized air cathode, 6M KOH/0.2M zinc acetate electrolytes and zinc foil anode. The battery was operated at the current density of 20 mA/cm2and its charge/discharge potential was 1.95V/1.15V, respectively. In addition, it showed stable performance with >80% coulombic efficiency over 1000 recharge cycles.

Acknowledgement: Authors would like to thank the Bureau of Energy (BOE), Ministry of Economy Affair (MOEA), Taiwan for the financial support.

References:

[1] J. W. D. Ng, M. Tang and T. F. Jaramillo. Energy Environ. Sci. 2014, 7, 2017.

[2] J. Masa, W. Xia, I. Sinev, A.Q. Zhao, Z.Y. Sun, S. Grutzke, P. Weide, M. Muhler, W. Schuhmann, Angew. Chem. Int. Ed. 2014, 53, 8508.

[3] S. Hu, T. Han, C. Lin, W. Xiang, Y. Zhao, P. Gao, F. Du, X. Li, and Y. Sun. Adv. Funct. Mater. 2017, 1700041.
High-Performance Supercapacitors Based on Graphitic Nanofibers/Nickel Sulfide Composite Electrodes
Authors: Tsai Yi-Hung , Chen I-Ching , Hsieh Chien-Kuo , Lin Jeng-Yu
Published: February 2020

Fossil fuel depletion, environmental pollution, and global warming have attracted interest in developing green and replaceable energy storage devices. Among various energy storage devices, supercapacitors (SCs) have been widely recognized in a wide range of applications in energy storage over the past decade, such as electric vehicles, mobile electronic devices, large industrial equipment, memory backup systems, and military devices. It is due to their unique properties including high power capability, long cycle lifetime, and fast charge/discharge rate.

In this work, nickel sulfide (Ni3S2) nanosheets were growth on the surface of graphitic-nanofibres (GNFs) by using pulse-reversal (PR) electrodeposition method. Compared to the pristine Ni3S2 electrode with discharged capacitance of 461 F g-1, the GNFs@ Ni3S2 electrode revealed a higher capacitance of 635 F g-1 at the same charge-discharge current density of 0.5 mA cm-2. The GNFs@ Ni3S2 electrode still retained 79% of the capacitance at 0.5 mA cm-2 when it was charged/discharged at 4 mAcm-2. Furthermore, the GNFs@ Ni3S2 electrode showed great electrochemical stability. For instance, the GNFs@ Ni3S2 electrode displayed 90% of initial capacitance after the consecutive 200 cycles charged/discharged at current density of 0.5 mAcm-2.
Transition Metal Triggered Electrochemical Interphases in Sodium-Ion Batteries
Authors: Mu Linqin , Rahman Muhammad Mominur , Lin Feng
Published: February 2020

Sodium-ion batteries are regarded as one of the most promising electrochemical energy storage devices because of their predicted advantages such as improved sustainability of sodium resources and significantly reduced cost. A large number of studies have been conducted to synthesize sodium layered oxide cathode materials that contain various transition metal elements (e.g., Ni, Mn, Co, Fe, Cu, Cr, V, Ti). Although these materials are structurally similar to the layered oxide materials in lithium ion batteries, they exhibit many distinct charging/discharging behaviors during Na+ deintercalation/intercalation. For instance, the multi-phase transformation accompanied with multi-voltage plateau, which is related to Na+ and vacancy ordered configuration, prevails in sodium layered oxide cathode materials and have been previously studied by synchrotron X-ray and neutron diffraction. Fe4+/Fe3+ redox couple, which is electrochemically inactive in the lithium counterparts, are extensively explored and implanted into sodium layered oxide cathode materials on account of further reducing the cost of sodium ion batteries. To deliver the practical promise that sodium ion batteries hold, however, methods need to be established to tackle fundamental challenges in sodium ion batteries, including structural and chemical transformations of the electrode materials, nature of the electrode-electrolyte interfacial reactions, and rate-determining steps in the fast charging. These challenges are rooted in the interfacial charge transfer processes and determine battery characteristics such as energy density, power density, and safety. Herein, we report the interfacial descriptors such as atomic orbitals and local coordination that drive the interfacial reactions and phase transformation. We then develop a conceptually new strategy, that is controlling the characteristics of transition metal-oxygen bonds, to stabilize the interphases and accelerate the charge transfer processes.
Initiation of Intergranular Corrosion on Extruded AA6005 Aluminium Alloy with Low Copper Content
Authors: Kumari Shilpa , Walmsley John Charles , Lunder Otto , Nisancioglu Kemal
Published: February 2020

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

References

[1] M. Hurlen Larsen, J. C. Walmsley, O. Lunder, and K. Nisancioglu, J. Electrochem. Soc., 157, C61 (2010).

[2] K.Shimizu, K.Nisancioglu, ECS Electrochemistry Letters, 3 (9) C29-C31 (2014).
On the Corrosion of the Lightweight Compositionally Complex Alloy Altivcr
Authors: Qiu Yao , Birbilis Nick
Published: February 2020

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

There is considerable current interest in identifying alloying elements for magnesium which produce an intrinsically corrosion resistant surface, thus precluding the need for additional protection by surface treatments and coatings. Recent work has demonstrated the promise of certain group IV and V elements as binary micro-alloying additions, which produce significant reduction in the corrosion rate of Mg 1,2. In the case of alloyed arsenic (As), a well-known cathodic poison, the reduced rate of corrosion is principally attributed to a profound suppression of cathodic activity on transition-metal impurity containing phases by inhibiting recombination of atomic hydrogen 3. Recent work has also demonstrated a similar phenomenon for Ge alloyed Mg 2, although the underlying reasons are less obvious than for the case of As. To clarify the role of Ge in significantly reducing the corrosion rate of Mg, an in situ scanning vibrating electrode technique (SVET) is herein employed to study localised corrosion behaviour of Mg-Ge alloys at open circuit conditions and during anodic polarisation when immersed in chloride containing aqueous solution. Upon immersion in the absence of external polarisation in aqueous solution containing concentrations of 0.5 M NaCl and below, SVET-derived area-averaged anodic current densities are shown to be extremely low, with no visible evidence of breakdown in the form of the dark filiform-like tracks reported over 24 h (and up to 90 h for a concentration of 0.1 M). However, when using concentrations of 1 M NaCl (aq) and greater, filiform-like localised corrosion features become established after initiation periods of ca.2 h or longer. In contrast to pure Mg, no cathodic activation of filament clusters are observed and residual tracks are shown to develop a white colour instead of the typical surface blackening observed on pure Mg. The addition of Ge is shown to strongly depress free corrosion potential (Ecorr) compared to pure Mg and it is proposed that it acts to maintain Ecorrbelow the apparent breakdown potential indefinitely for chloride ion concentrations of 0.5 M and lower. Under galvanostatic anodic polarisation, hydrogen evolution rates are significantly lower in comparison to pure Mg and no localised cathodic activity is detected for the duration of the experiment. In this respect the behaviour of Ge-alloyed Mg closely mirrors that of the Mg-As system, but with the benefit of intrinsic corrosion resistance bestowed by a non-toxic alloying addition.

References:

1. N. Birbilis , G. Williams, K. Gusieva, A. Samaniego, M.A. Gibson and H.N. McMurray, Electrochem. Commun., 34 (2013), 295.

2. R. L. Liu, M. F. Hurley, A. Kvryan, G. Williams, J. R. Scully and N. Birbilis, Nature Scientific Reports, 6: (2016) 2874.

3. G. Williams, H. Ap Llwyd Dafydd, H.N. McMurray and N. Birbilis, Electrochim. Acta, 219 (2016) 401.
Improving the Corrosion Behavior of Magnesium-based Metal Matrix Composites
Authors: Esmaily Mohsen , Svensson Jan-Erik , Johansson Lars-Gunnar
Published: February 2020

Magnesium-based metal matrix composites (Mg-based MMCs) are promising lightweight materials with many applications in the automotive and aerospace industries. Mg-based MMCs combine the high specific strength and good castability of Mg alloys with the excellent properties of the reinforcement. The reinforcing material is typically a ceramic, which exhibit tempting properties such as high melting point, excellent wear resistance, and high stiffness. The main driving force behind the development of Mg-based MMCs is that conventional Mg alloys show insufficient yield strength, damping capacity, wear, fatigue, thermal shock and creep resistances for many high-end applications, and thus, MMCs usually outperform their monolithic counterparts in this respect. However, it has been shown that Mg-based MMCs corrode faster than their monolithic counterparts. To date, attempts to produce corrosion-resistant Mg-based MMCs have failed, largely due to a lack of fundamental understanding of the corrosion phenomena occurring in this class of materials. In this paper, we studied the atmospheric corrosion behavior of silicon carbide (SiC)-reinforced Mg-based MMCs produced via a semi-solid casting method. We investigated the MMCs’ microstructure using the scanning transmission electron microscope (STEM/EDX) and electron energy loss spectroscopy (EELS). It was shown that the corrosion resistance of Mg-based MMCs can be improved via changing the casting parameters and pre-treatment of the reinforcements. A modified Mg-based MMCs exhibit favorable microstructural characteristics e.g., a lower fraction of pores and less numbers of ''undesirable'' intermetallic particles. We discuss, in detail, the atmospheric corrosion mechanism of Mg-based MMCs and formulate a working hypothesis for producing cast Mg-based MMCs that show enhanced atmospheric corrosion behavior.
Development of pH Sensing CFDE to Investigate Anodic Dissolution of Magnesium
Authors: Miyazawa Kei , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki
Published: February 2020

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

The anodic polarization curve measurement of Mg and pH measurement was carried out by developed system. It was confirmed that the increase of pH is corresponded to the increase of anodic current of Mg with hydrogen generation.

Reference

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

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

[3] G. Song, A. Atrens, D. Stjohn, X. Wu, and J. Nairn, Corros. Sci., 39, 1981 (1997).

[4] L. Rossrucker, A. Samaniego, J.-P. Grote, A. M. Mingers, C. A. Laska, N. Birbilis, G. S. Frankel, K. J. J. Mayrhofer, J. Electrochem. Soc., 162, C333-C339 (2015).

[5] G. S. Frankel, A. Samaniego, and N. Birbilis, Corros. Sci., 70, 104 (2013).

[6] G. Williams, N. Birblis, and H. N. McMurray, Electrochem. Commum., 36, 1 (2013).

[7] G. L. Song and A. Atrens, Ave. Eng. Mater., 1, 11 (1999).

[8] G. L. Song and A. Atrens, Ave. Eng. Mater., 5, 837 (2003).

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

A debate about the critical step in localized corrosion has raged for decades. Some researchers focus on the composition and structure of the passive film associated with the initial breakdown of the film, whereas others consider that the susceptibility to pitting is controlled by the pit growth kinetics and the stabilization of pit growth. The basis for a unified theory of pitting is presented here in which pit stability considerations are controlling under aggressive conditions (harsh electrolytes and extreme environments and/or susceptible microstructures) and the passive film properties and protectiveness are the critical factors in less extreme environments and/or for less susceptible alloys.

This work was supported as part of the Center for Performance and Design of Nuclear Waste Forms and Containers, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0016584.
(Invited) Characterizing Crevice Corrosion Processes Electrochemically, Microscopically, and Spectroscopically
Authors: Ebrahimi Nafiseh , Noel Jamie , Shoesmith Dave
Published: February 2020

Due to the occluded nature of the process, crevice corrosion is difficult to investigate electrochemically, microscopically and spectroscopically. The electrochemistry/chemistry occurring within propagating crevices can be highly localized and difficult to characterize. With an emphasis on Ti and Ni alloys, we have developed a range of methodologies to determine the electrochemical/chemical details of crevice corrosion processes and how they are influenced by the compositional and microstructural properties of the materials.

On both alloy categories crevice propagation can be supported by both external and internal cathodic processes. The kinetics of the external process (O2 reduction) can be followed electrochemically using a galvanic coupling technique, while the internal process (H+ reduction), although detectable by its influence on the O2 reduction kinetics, cannot be directly followed in real time. Which of these two reactions is dominant is very dependent on alloy composition and microstructure.

For Ti alloys, the microstructure is very dependent on the added alloying elements (e.g., Ni, Pd, Ru) and the content of unavoidable impurities such as Fe, and perhaps also Mo and Cr. Their distribution in the uncorroded alloy can be determined using atomic probe tomography and their redistribution, as a consequence of a period of crevice propagation, by dynamic secondary ion mass spectrometry.

By comparison to Ti alloys, Ni-based alloys (in particular Ni-Cr-Mo alloys) are free of segregated secondary phases, and possess high quality, low energy grain boundaries. These two qualities can be demonstrated using electron backscatter diffraction, transmission electron microscopy and electron energy loss spectroscopy. However, while the quality of the grain boundaries is a key feature in controlling the initiation of crevice corrosion, it is the alloy composition which exerts the dominant influence on the accumulation and distribution of corrosion damage by depositing Mo oxides at propagating sites, a process that can be demonstrated by correlating the damage distribution, determined by confocal laser scanning microscopy, with the accumulation of molybdates, confirmed by microRaman spectroscopy.

Using this combination of electrochemical, microscopic and spectroscopic techniques we are presently determining the influence of alloy composition on the relative importance of internally and externally supported crevice propagation. Also, we are developing the technique of X-ray photoelectron spectroscopic imaging to demonstrate the self-healing capability conferred on these alloys by the inclusion of Mo.