bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Towards Solving the Long Standing Mystery of the Chemical State of Co in PtxCo1-X to Boost HOR and ORR
Authors: Oezaslan Mehtap , Weber Philipp , Weber Daniel Jochen , Dosche Carsten 
Published: December 2020

Recently, Pt-based core-shell nanoparticles (NPs) have emerged as highly active catalyst materials to accelerate the sluggish oxygen reduction reaction (ORR) in acidic media as well as the hydrogen oxidation reaction (HOR) in alkaline. Less attention has been payed to the chemical state of the less noble metal after forming core-shell NPs. Intuitively; a metallic state of the less noble metal inside the particles has been suggested from many research groups.
In this talk, we will show a new catalyst concept for Pt-Co nanoparticles by manipulating the surface arrangement and composition induced by the reaction conditions. More precisely, our catalysts exhibit superior Pt surface area-based specific activities (up to 10-fold) and Pt mass-based activities (up to 5-fold) towards the ORR compared to commercial Pt/C at 0.95 VRHE. In addition, we will show the influence of the chemical state and surface enrichment of the cobalt on the HOR activity in alkaline media.
Altogether, we will solve the long standing mystery of the chemical state of the cobalt and its distribution for PtxCo1-x nanoparticles and its remarkable effect on the catalytic performance for HOR and ORR.
(Keynote) 10-Minute Fast Charging of High Energy Density Lithium-Ion Batteries with Superior Cycle Life
Authors: Yang Xiao-Guang , Liu Teng , Ge Shanhai , Wang Chao-Yang 
Published: December 2020

Adding 200 miles of driving range in 10 min by charging at 400 kW, the so-called extreme fast charging (XFC), is considered as the key to mainstream adoption of electric vehicles (EVs). No EVs today, however, can withstand 400-kW charging power due to the risk of Li plating, which severely deteriorates battery life.
Recently, our group reported an asymmetric temperature modulation (ATM) method that enables 10 min charging of high-energy EV cells with remarkable cycle life. [1] The key concept of the ATM method is to charge a Li-ion cell at an elevated temperature of 60oC and discharge (and stores) the cell at the cool ambient temperature (Figure 1). The high charging temperature effectively eliminates Li plating thanks to the enhanced kinetics and transport, and the limited time of exposure to 60oC (~10 min per cycle, or 0.1% of the lifetime of an EV) prevents severe SEI growth. We demonstrated that a high-energy cell with a specific energy of 209 Wh/kg sustained 2500 cycles of 10-minute XFC with only 8.3% capacity loss, far exceeding the US DOE target.
In this talk, we will give a comprehensive discussion of the ATM method. Also, we will share our latest progress on the XFC of cells with much higher specific energy (260 Wh/kg).

References

[1] X.G. Yang, T. Liu, Y. Gao, S. Ge, Y. Leng, D. Wang, C.Y. Wang, Joule, 3 (2019) 3002-3019.

Figure 1
Sn–Ni Alloy Anode Pre-Doped in Vinylene Carbonate Containing Electrolyte for Lithium-Ion Capacitor
Authors: Nara Hiroki , Nakamura Yusuke , Ahn Seongki , Momma Toshiyuki , Sugimoto Wataru , Osaka Tetsuya 
Published: December 2020

Lithium–ion capacitor (LIC), which is composed of non–Faraday reaction cathode used in electric double layer capacitor (EDLC), and Faraday reaction anode used in lithium–ion battery (LIB), is a promising energy storage device for electric vehicles, because LICs are ranked between LIBs and EDLCs for energy density and power density.1 LIC with Sn–Ni alloy anode is superior to that with a graphite anode in energy and power density. 2 For the purpose to improve its cycle durability to a practical level, the effect of vinylene carbonate (VC) which affects positively for LIBs, was investigated.
Sn–Ni alloy anode was electrodeposited according to the previous report.3 The Sn–Ni alloy anode was pre-doped (pre-lithiated) by several charge–discharge cycles in an electrolyte with or without vinylene carbonate (VC). The LICs composed of an activated carbon cathode and the pre-doped Sn–Ni alloy anode were evaluated.
The VC additive was revealed to affect positively during a pre-doping process and to affect negatively during charge–discharge cycling to the cycle performance of LIC. The difference for the additive effect was discussed by the potential changes and the morphology changes of the anode, revealing that VC formed a polymer-like SEI during the pre-doping process, suppressing deactivation of Sn caused by cracking growth and peeling-off during charge–discharge cycling. In contrast, VC was decomposed continuously during charge–discharge cycling with consuming pre-doped lithium. Thus, a strategy to use additives for alloying anode system was established. Finally, the excellent cycle durability (more than 10000 cycles with the capacity retention of 72.3%) of the LIC with high volumetric energy density of 38.9 Wh/L at 120 W/L was firstly demonstrated (Fig. 1).

Acknowledgement

This work is partially supported by Advanced Low Carbon Technology Research and Development Program of the Japan Science and Technology Agency (JST-ALCA, JPMJAL1008).

References

K. Naoi, S. Ishimoto, J. I. Miyamoto, and W. Naoi, Energy Environ. Sci., 5, 9363–9373 (2012).

S. Ahn, Y. Nakamura, H. Nara, T. Momma, W. Sugimoto, and T. Osaka, J. Electrochem. Soc., 166, A3615–A3619 (2019).

H. Mukaibo, T. Sumi, T. Yokoshima, T. Momma, and T. Osaka, Electrochem. Solid-State Lett., 6, A218 (2003).

Figure 1
Investigation of Pd-Containing Co3O4/C Catalysts for Oxygen Reduction Reaction
Authors: Stagniunaite Raminta , Kepeniene Virginija , Vaiciuniene Jurate , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus 
Published: December 2020

Because of the energy crisis, air pollution and global warming it is necessity of technologies that creates sustainably, highly efficient and green energy resources. That is the reason why fuel cells are one of the best power sources – they convert chemical energy into electrical energy and do not contaminate the environment. The main difference between fuel cells and usual batteries is that fuel cell requires a continuous source of fuel (ethanol, methanol, ethylene glycol etc.) and oxygen to sustain the chemical reaction. It is well known that Pt-based catalysts are usually used in fuel cells, however recently, the search of new catalysts with reduced amount of Pt or even non-noble metal catalysts is in progress. Pd-based electrocatalysts have been studied as alternative because of their lower cost and efficient electrocatalytic activities for oxygen reduction (ORR) and fuel oxidation (ethanol, methanol, ethylene glycol etc.) reactions.
In this paper we investigated electrocatalytic activity of the Co3O4/C based Pd catalysts towards oxygen reduction reaction. The new catalysts were prepared using few different synthesis steps. At first Co3O4 was deposited on carbon using microwave irradiation at 120 ºC for 3h. Then the obtained Co3O4/C powder was impregnated by Pd in 0,0014 M PdCl2 solution. Further, part of the Co3O4/C powder and impregnated Co3O4/C powder was annealed at 400 ºC for 3h. Depending on the fabrication conditions four different composition of catalyst was obtained. The composition, morphology and structure of the prepared catalysts were characterized using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Electrochemical measurements have been carried out using linear sweep voltammetry (LSV) using rotating disk electrode (RDE) method.
The XRD and XPS data have been showed that the constitution of obtained catalysts was following: Co3O4/C was obtained after microwave irradiation heating, PdCox(OH)y/C constitution was estimated for catalyst impregnated in 0,0014 M PdCl2 solution and Co3O4/C-T and PdOCo3O4/C catalysts were obtained annealed at 400 ºC for 3h.
It has been found that the impregnation of the Co3O4/C substrate by Pd as well as annealing of primary materials strongly enhanced electrocatalytic activity of investigated catalysts towards oxygen reduction reaction. The ORR activity of the catalysts has been found to increase as follows Co3O4/C < Co3O4/C-T < PdCox(OH)y/C < PdOCo3O4/C ≤ Pt/C. The ORR onset potential reached the most positive potential values in the same line and was equal to 0.78 < 0.83 < 0.91 < 0.92 < 0.95 V.
It has been determined that the PdOCo3O4/C catalyst showed the highest electrocatalytic activity for ORR compare to the PdCox(OH)y/C and Co3O4/C catalysts and was very similar to Pt/C.
Investigation on Preparation Conditions for High Performance MEA of Alkaline Membrane Fuel Cells
Authors: Lee Hyejin , Shin Dongwon , Bae Byungchan 
Published: December 2020

Recently, AMFCs (Alkaline Membrane Fuel Cell) using non-platinum group metal (PGM) based catalysts and having good efficiency have attracted attention as an alternative to PEMFCs. However, in spite of these important advantages, the development of materials for AMFC is still an important issue because the AMFC performance based on the platinum catalyst is still superior to that of non-PGM in an alkaline environment. [1]
We here present various preparation methods of a membrane electrode assembly (MEA) in order to increase the performance of AMFCs. Kinds of the gas diffusion layer, solvents for catalyst slurry, commercial binders for electrodes, and PGM-free catalyst were the main parameters of MEA performance. For the exact comparison of each parameter, reference MEA was selected by the use of commercial parts such as 39BC (SIGRACET), Fumion membranes, and binders (FuMA-Tech Inc.,), Pt/C and PtRu/C (Tanaka Kikinzoku Kogyo K.K.). The cell test was performed at 70 °C and 100% RH with 1 L/min H2/O2 to both anode/cathode, respectively.
As a result, the FAA-3-50 membrane with PGM catalyst layers showed excellent performance of over 1,000 mA/cm2 at 0.6 V. In addition, the performance of the PGM-free cathode catalyst was over 450 mA/cm2, which showed a possibility to non-PGM AMFCs. We observed the I-V curve, electrochemical surface area, linear sweep voltammograms, and ohmic resistance. Experimental conditions and results will be presented in detail.

References

[1] H. A. Firouzjaie, W. E. Mustain, ACS Catal., 10 (2020) 225-234
(Invited) Development of Versatile Polymer Materials for Anion Exchange Membranes in Electrochemical Energy Conversion Technology
Authors: Bae Chulsung 
Published: December 2020

Anion exchange membranes (AEMs) based on hydroxide-conducting polymers are a key component for anion-based electrochemical energy technology such as fuel cells, electrolyzers, and advanced batteries. Although these alkaline electrochemical applications offer a promising alternative to acidic proton exchange membrane electrochemical devices, access to alkaline-stable and high-performing polymer electrolyte materials has remained elusive until now. Despite vigorous research of AEM polymer design, examples of high-performance polymers with good alkaline stability at an elevated temperature are uncommon. Traditional aromatic polymers used in AEM applications contain a heteroatomic backbone linkage which is prone to degradation via nucleophilic attack by hydroxide ion.
In this presentation, I will highlight recent progress at the Bae group of Rensselaer Polytechnic Institute in the development of advanced hydroxide-conducting polymers and technology transfer effort to commercialize materials for AEM applications. We have developed new synthetic methods that produce polymer design made of all C−C bond backbone and a flexible chain-tethered quaternary ammonium group and that provide an effective solution to the problem of alkaline stability. The advantage of good solvent processability, synthetic versatility, and convenient scalability of the reaction process has generated considerable interest of these polymers, and they are considered leading candidates for commercial standard AEM. AEM fuel cells, electrolyzer, and vanadium redox flow battery tests of some of the developed polymer membranes showed excellent performance, suggesting that this new class of AEMs open a new avenue to electrochemical devices with real-world applications.
Improving Stability and Kinetics of Alkaline HOR Catalysts – Towards Reduced System Cost
Authors: Speck Florian Dominik , Ali Farhan S. M. , Paul Michael T. Y. , Singh Ramesh-Kumar , Böhm Thomas , Thiele Simon , Dekel Dario R. , Kallio Tanja , Cherevko Serhiy 
Published: December 2020

Anion exchange membrane (AEM) fuel cells (FC) show great promise in overcoming monetary drawbacks of currently state of the art proton exchange membrane (PEM) FC, that rely on expensive Pt catalysts for both the hydrogen oxidation reaction (HOR) as well as the oxygen reduction reaction (ORR). With recent advancements in demonstrating high ORR activity and stability of Fe-N-C catalysts in alkaline environments,1 the HOR suddenly became the bottleneck reaction towards high power density platinum group metal (PGM) -low or -free AEM-FCs. While application of PGM-free ORR catalysts is an eventual goal, current state of the art NiM nanoparticles show relatively poor performance in terms of both activity and irreversible oxidation and dissolution.2 Hence, at least for some time, one will need to rely on PGM catalysts for alkaline HOR, where the biggest challenge will be lowering the loading and meanwhile increasing the stability in an alkaline environment. To this end, fundamental understanding of surface processes is required.
In this work we investigate model CeOx covered Pt and Pd electrocatalysts as benchmark materials for the HOR reaction.3,4 To prepare such model electrodes, we use physical vapor deposition and atomic layer deposition techniques for formation of PGM and a variable thicknesses CeOx surface layers, subsequently. Activity and stability of the CeOx@Pt and CeOx@Pd electrodes are studied in common rotating disk electrode (RDE) and on-line inductively coupled plasma mass spectrometry setups, respectively. External analytics, e.g. X-ray photoelectron spectroscopy (XPS), are used to further characterized the electrodes before and after degradation studies. We show that stability of the electrodes at the higher anodic potentials can be improved greatly by tuning the thickness of the CeOx layer. Interestingly, this can be achieved without sacrificing and even with a significant enhancement in the HOR activity. This unique performance is explained by assuming that the deposited CeOx films form an ion selective semipermeable passivation layer on the surface of Pd and Pt. We anticipate that as a next logical step such layers can be used to stabilize PGM free Ni alloys and reach the goal of having completely PGM-free FCs.
References
1. P. G. Santori, F. D. Speck, J. Li, A. Zitolo, Q. Y. Jia, S. Mukerjee, S. Cherevko and F. Jaouen, J. Electrochem. Soc., 166, F3311 (2019).
2. E. S. Davydova, F. D. Speck, M. T. Y. Paul, D. R. Dekel and S. Cherevko, ACS Catalysis, 6837 (2019).
3. N. M. Markovića, S. T. Sarraf, H. A. Gasteiger and P. N. Ross, J. Chem. Soc., Faraday Trans., 92, 3719 (1996).
4. H. A. Miller, F. Vizza, M. Marelli, A. Zadick, L. Dubau, M. Chatenet, S. Geiger, S. Cherevko, H. Doan, R. K. Pavlicek, S. Mukerjee and D. R. Dekel, Nano Energy, 33, 293 (2017).
AuCo3O4/C – Different Fabrication Methods and Application for Fuel Cell Reactions
Authors: Kepeniene Virginija , Stagniūnaitė Raminta , Vaičiūnienė Jūratė , Jasulaitienė Vitalija , Tamašauskaitė-Tamašiūnaitė Loreta , Norkus Eugenijus 
Published: December 2020

Nanoscale materials are very important in many industries. There are many various synthesis methods such as adsorption, electroless deposition, galvanic displacement or microwave irradiation methods which let to fabricate nanomaterials. Lately, microwave irradiation is used as a rapid convenient method which gives excellent yields and higher purity of the products than conventional methods. Nanoparticles-based catalysts are usually heterogeneous catalysts broken up into metal nanoparticles in order to speed up the catalytic process. Metal nanoparticles have a higher surface area so there is increased catalytic activity because more catalytic reactions can occur at the same time. Nanoparticles catalysts can also be easily separated and recycled with more retention of catalytic activity than their bulk counterparts. Nanoparticles of gold are attractive for their interaction with other compounds and property to attract catalytic active groups.
In this work, we investigated the influence of synthesis method to the electrocatalytic activity of catalyst. Therefore, Au nanoparticles were deposited on the Co3O4/carbon (Co3O4/C) substrate using microwave irradiation AuCo3O4/C-1, AuCo3O4/C-2 and impregnation AuCo3O4/C-3 methods. The composition, morphology and structure of the prepared catalysts were characterized using Inductively Coupled Plasma Optical Emission Spectroscopy, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and X-ray diffraction. The electrocatalytic properties of prepared catalysts were investigated towards ethylene glycol electro-oxidation and oxygen electro-reduction reactions in an alkaline medium. Electrochemical analysis was performed using a rotating disc electrode and the Autolab electrochemical workstation.
It has been determined, that in all cases modification of Co3O4/C catalyst by gold improved the electrocatalytic properties of synthesized AuCo3O4/C catalysts. As-prepared AuCo3O4/C catalysts showed an enhanced electrocatalytic activity towards the electro-oxidation of ethylene glycol and electro-reduction of oxygen in an alkaline medium compared with that obtained for the Co3O4/C or Au/C catalysts. The AuCo3O4/C catalysts prepared by microwave irradiation heating demonstrated up to 3 times higher electrocatalytic activity towards the electro-oxidation of ethylene glycol and up to 2 fold higher electrocatalytic activity towards electro-reduction of oxygen compared with that of the AuCo3O4/C catalyst prepared using impregnation.
pH-Controlled Growth of Ni-Fe Layered Double Hydroxide Electro-Catalyst for Water Oxidation with Exceptional Operational Stability
Authors: Mehdi Muhammad , Cho Hyun-Seok , Cho Won-Chul , Kim Sang Kyung , Kim MinJoong , Kim Chang-Hee 
Published: December 2020

Ni-Fe layered double hydroxide (LDH) is a potential OER electro-catalyst in water electrolysis due to its layered open structure, rapid diffusion of reactant, good anion exchange and excellent hydroxyl adsorption. Its OER activity has been well reported at constant applied voltage. However, the water electrolyser utilizes renewable energy due to which it suffers irregular power supply that consequently affects its electrode activity. Therefore, the development of a stable Ni-Fe LDH under dynamic operation conditions is required. Herein, we performed pH-controlled growth of NiFe LDH (1:1) on Fe substrate in nickel sulfate solution by oxygen sparging. The prepared LDH requires a low OER overpotential of ~270 mV vs. Hg/HgO at 200 mA/cm2 in 1M KOH solution. Considering the potentiodynamic polarization curve of Ni-Fe LDH, its OER region is above 0.5 V (vs. Hg/HgO) and shutdown region is below 0.3 V (vs. Hg/HgO). The voltage fluctuation between both regions may result in phase change and structural distortion. Therefore, three stability regimes are important to consider for an actual operational stability test; upper OER regime I (constant 0.75 V (vs. Hg/HgO)), one-minute lower to upper OER regime II (0.5 to 0.75 V (vs. Hg/HgO)) and one-minute on-off regime III (0.3 to 0.75 V (vs. Hg/HgO)). The electrochemical characterization before and after each 12 hours regime showed no degradation and steady kinetics (38 mV/dec). The morphological and surface analysis using SEM, XRD, TEM and XPS confirmed that the LDH structure remained preserve after each regime.
Fig. 1: Operational stability test of Ni-Fe LDH prepared by pH-controlled growth under three regimes and embedded IR-corrected polarization curve after each regime.

Figure 1
Local Measurement of Anode Current Collector Potential in a PEM Water Electrolyzer
Authors: Becker Hans , Castanheira Luis , Smith Graham , Dickinson Edmund J. F. , Hinds Gareth 
Published: December 2020

The current collector (CC) components (bipolar plate and porous transport layer) of a polymer electrolyte membrane water electrolyser (PEMWE) comprise one of the highest proportion of the cost of the stack [1]. It is widely accepted that the PEMWE CC material needs to withstand the relatively high potentials encountered at the anode electrode, with ex situ qualification testing typically carried out at an applied potential of at least 2 V vs the standard hydrogen electrode (SHE). As a result, platinum-coated titanium is the common material of choice. However, we offer a counter hypothesis that it is unlikely that the corrosion potential of the anode CC is equal to that of the anode electrode due to the very low ionic conductivity of the pure water phase separating the two components.
In this work, an innovative in situ reference electrode consisting of a Nafion®/H2SO4 salt bridge connected to a reversible hydrogen electrode is used to measure the corrosion potential of the anode CC during PEMWE cell operation. Using this technique, we demonstrate for the first time that the corrosion potential of the anode current collector is effectively decoupled from that of the anode electrode [2]. Furthermore, we demonstrate that carbon paper can be applied as anode CC material without any noticeable corrosion taking place.
The implications of this work are that significantly cheaper materials such as carbon or carbon-coated stainless steel can be used for CC components, which could reduce the cost of PEMWE technology substantially. The key advance is the use of a thin porous spacer layer between the anode and the CC. Factors that may influence the implementation of this new concept are discussed, including the influence of spacer layer tortuosity and water conductivity on the corrosion potential of the CC.

References

[1] K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar, M. Bornstein, Perspectives on low-temperature electrolysis and potential for renewable hydrogen at scale, Annual Review of Chemical and Biomolecular Engineering 10 (2019) 219–239.
[2] H. Becker, L. Castanheira, G. Hinds, Local measurement of current collector potential in a polymer electrolyte membrane water electrolyser, Journal of Power Sources 448 (2020) 227563.

Figure 1