bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer Electrolyte Membrane Fuel Cells (PEMFCs) Catalyst Layer Based on the Triple-Phase Separated Nanostructure
Authors: Seo Dongjun , Kim Hansung , Kim Tae-Young 
Published: February 2020

The eco-friendly power generation mechanism and high energy density of polymer electrolyte membrane fuel cells(PEMFCs) have been steadily researched in many institutions and countries that are aiming for sustainable development and have improved to a commercially available level of performance. However, electrode production using platinum has high price and supply problem, so research is being carried out to achieve high performance using small amount Pt catalyst. In order to produce MEA that meet these requirements, this study understands the three phase boundary, which is the basis of the catalytic reaction, and aims to design an electrode layer suitable for a polymer electrolyte membrane fuel cell and suggest a production method.
In the conventional electrode manufacturing process, the mixed liquid slurry is used, so the ionomer is randomly distributed in the electrode layer after drying. Therefore, it was difficult to adjust to exist in the optimal position favorable to the reaction. Especially, the thick ionomer on carbon supports is located in the catalyst layer inevitably has a structure that is difficult to reach the Pt surface because the reaction gas supplied through the pores is diffused. In the case of cathodes, Pt surface is known to form a low oxygen fraction of 1/20 compared to pores, which indicates the limit of performance with high mass transfer resistance.
In this study, Ionomer was coated on a carbon support and then solidified. After that, the electrode was made by mixing with the commercial catalyst at the optimal ratio, so that the movement path of the proton and the electron could be separated independently. We are trying to suggest a new recipe to make a catalytic layer that can induce high oxygen pressure on the surface of the catalyst and introduce a pore distribution that is effective for electrochemical reactions.
In addition, the catalytic layer produced by this method was able to realize an independent path because the contact of each part was maintained well. As a result, the pores effective for electrochemical reactions were widened to achieve the performance of commercial electrodes even at a low level of 0.2mgPt/cm2. Moreover, this method can be used to produce high-performance electrodes at a low price using a small amount of expensive platinum catalysts, and especially in the related industries, because all materials used in the manufacturing method are commercially used and do not require specially manufactured equipment.
Ru-Functionalized Mo2c Nanoparticles in-Situ Grown on Biomass-Derived 3D Porous Carbon Framework for Catalytic Hydrogen Evolution
Authors: Zhang Zhen , Feng Qi , Li Hui , Wang Haijiang 
Published: February 2020

Developing highly efficient and long-durable electrocatalysts toward the hydrogen evolution reaction (HER) is highly desirable for implementation of the water-splitting to produce high-purity H2 at large scale.[1] Although Pt-group metals so far have been proven to be superior electrocatalysts for HER, the high-cost and scarcity heavily inhibit their widespread application. To date, a series of HER electrocatalysts based on transition metal carbides have been developed. However, in most of these cases, their catalytic activity and durability still need to be improved to compete with Pt-based electrocatalysts.[2, 3] As a cheaper alternative to Pt, Ru possesses similar bond strength with hydrogen, guaranteeing the promise for catalytic hydrogen evolution.[4, 5] In this study, we demonstrate a novel strategy for the preparation of Ru-functionalized Mo2C nanoparticles embedded in popcorn-derived three-dimensional (3D) porous carbon framework.
The synthesis mainly involves two steps: (i) the activation of popcorn by KOH and the co-assembly with Ru and Mo precursors. With the help of activation treatment, the popcorn can easily disperse in the solution and absorb Ru and Mo precursor. (ii) freeze-drying followed by in situ annealing treatment. The crystallization of Ru nanoparticles, in-site growth of Mo2C nanoparticles and the carbonization of porous popcorn were simultaneously performed during annealing process. Due to the synergistic effects between Ru and Mo2C nanoparticles, the composite catalyst showed higher HER activity.
Figure 1. a) A schematic diagram showing the organization of the Mo2C@Ru. b) HER polarization curves of Mo2C, Ru and Mo2C@Ru with the iR drop correction, acquired at a scan rate of 5 mV s-1 in 0.5 M H2SO4.
References
[1] Q. Feng, X.Z. Yuan, G. Liu, B. Wei, Z. Zhang, H. Li, H. Wang, Journal of Power Sources, 366(2017) 33-55.
[2] K.-H. Liu, H.-X. Zhong, S.-J. Li, Y.-X. Duan, M.-M. Shi, X.-B. Zhang, J.-M. Yan, Q. Jiang, Progress in Materials Science, 92 (2018) 64-111.
[3] M. Miao, J. Pan, T. He, Y. Yan, Y. Xia Bao, X. Wang, Chemistry – A European Journal, 23 (2017)10947-10961.
[4] J. Mahmood, F. Li, S.-M. Jung, M.S. Okyay, I. Ahmad, S.-J. Kim, N. Park, H.Y. Jeong, J.-B. Baek,Nature Nanotechnology, 12 (2017) 441.
[5] J. Su, Y. Yang, G. Xia, J. Chen, P. Jiang, Q. Chen, Nature Communications, 8 (2017) 14969.

Figure 1
New Structure of Large-Sized Protonic Ceramic Fuel Cell with Porous Alloy
Authors: Hiraiwa Chihiro , Tawarayama Hiromasa , Higashino Takahiro , Okuno Kazuki , Han Donglin , Uda Tetsuya , Majima Masatoshi 
Published: February 2020

Introduction

Some perovskite oxides, such as doped BaCeO3 and BaZrO3 electrolyte-based protonic ceramic fuel cell (PCFC) have received increasing attention as electrolytes of reduced temperature to operate [1,2]. Furthermore, PCFC leads to the production of water vapor at the cathode side, which helps to improve the conversion efficiency of SOFC system. And it is possible to reduce the cost of the stack because inexpensive metal materials can be used for interconnectors in stacks. However most of the previous researches on PCFC are small-sized cell and it is necessary to further improve the power density. In this work, we reported that a cell stack of a new structure was designed and made with large-sized PCFC and porous alloys for anode and cathode current collector to improve power density, and the characteristics were evaluated.

Experimental

2.1 Preparation of large-sized PCFC
BaCe0.8Y0.2O3-δ(BCY20) and BaZr0.8Y0.2O3-δ(BZY20) were prepared by solid state reaction method and were mixed with NiO by a ball-mill to prepare an anode powder. The powder was pressed uniaxially under 40 MPa into anode pellet. On anode pellet BCY20 and BZY20 electrolyte layer were deposited by a screen printing and co-sintered at 1450 ºC for 10 hours. LSCF cathode powder was also deposited and sintered at 1000 ºC. Figure 1(A) shows an optical image of a large-sized PCFC.
2.2 Preparation of Ni and Ni-Sn porous metals
A polyurethane foam with interconnected cells was treated to become electrically conductive. This was followed by the application of a predetermined amount of nickel via electrodeposition. The base material, or plastic foam, was removed through heat treatment at 800 ºC. The remaining nickel was reduced in a reducing gas at approximately 1000 ºC to become a nickel porous metal. Next, the Ni porous metal was coated with a predetermined amount of Sn by electrodeposition. Additionally, this was heat-treated in a reducing gas at approximately 1000 ºC to become a Ni-Sn porous alloy by means of Sn diffusion into Ni. Figure 1(B) shows an SEM image of the surface of the Ni-Sn porous alloy [3].

Result

The power generating characteristics of a single-PCFC in which Ni-Sn porous alloy and Ni porous metal were applied as a cathode and anode collector was evaluated at the operating temperature of 600 ºC. Peak power densities of 500 mW/cm2 and 333 mW/cm2 were achieved, respectively, at 600 ºC and 500 ºC operating on hydrogen fuel.
[1] H. Iwahara, et al., Solid State Ionics, 61, 65 (1993)
[2] J. Dailly, et al., Journal of Power Sources, 240, 323 (2013)
[3] C. Hiraiwa, et al., International Journal of Hydrogen Energy, 42, 12567 (2017)

Figure 1
Synergy Effect of Mixed Precursor Infiltrated Cathode on Solid Oxide Fuel Cell Performance
Authors: Kim Jinhyeon , Shin Sung Soo , Choi Jiwoo , Lee Channyung , Shin Hyunho , Choi Mansoo 
Published: February 2020

The Solid oxide fuel cells (SOFCs) are promising alternative to combustion technology for electric energy production due to no emission and high efficiency in chemical to electric energy conversion. However, the commercialization of SOFCs is hindered by the high operating temperature, resulting in few of main problems, such as expensive system cost and short lifetime. Thus, while reduced-temperature SOFCs has been a long lasting interest in SOFC community, the sluggish oxygen reduction reaction (ORR) occurring at cathode at intermediate temperature is the most critical challenge for enhanced overall performance of SOFCs. In recent years, the surface modification of cathode materials by infiltration process shows outstanding performance. In this process, it is important to select the proper infiltrate materials since which play important role in enlarging active sites for ORR. However, the existing infiltration processes have limiting effect on performance of SOFC due to coarsening of particles at high temperature. Therefore, the selection of appropriate infiltrate materials along with the suppression of particle growth is the key requirement for enhanced ORR, dominating overall SOFC performance.
In this paper, we attempt to systemically investigate the various metal oxide as infiltrate material and extend active site for ORR by controlling the size of infiltrated oxide. The nitrate precursor of corresponding oxide was infiltrated into the cathode, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), in symmetric cell to test the effect of each infiltrated oxide on ORR. Among the tested samples, Pr infiltrated LSCF show lower polarization resistance (Rp) at 500 °C; 40 % lower Rp for Pr infiltrated LSCF than that of bare LSCF. Furthermore, mixed precursor of two different oxides, chemically inactive each other, were infiltrated. This process can effectively suppress particle growth at high temperature, resulting in more active site for ORR due to increased surface area. To confirm the morphology of infiltrated oxides anchored on the cathode surface, scanning electron microscope (SEM) and transmission electron microscopy (TEM) are performed.Also, electrochemical impedance spectroscopy (EIS), thermogravimetric analysis (TGA) and iodometric titration are conducted to understand correlation between produced oxygen vacancy by infiltrated oxide and ORR. In conclusion, this study shows that mixed precursor-infiltrated cathode has significant influence on ORR in SOFCs.
Effects of External Pressure on the Performance of Lithium Anode Cells
Authors: Nagpure Shrikant C. , Dufek Eric J. , Wood Sean M. , Dickerson Charles C , Liaw Boryann 
Published: February 2020

Rechargeable lithium metal anode batteries (RLB) have the potential to meet the Department of Energy’s 500 Wh/kg goal [1]. However, higher cycling efficiency and safety of these cells is challenged by the dendritic Li plating morphology. Li surface protective coating or electrolyte that can promote growth of stable solid electrolyte interphase from the reduction products can prevent dendritic growth of Li during plating. Another way to suppress the dendritic growth and facilitate more uniform Li surface morphologies is by applying the external pressure to the cell [2].
The external cell pressure can influence the Li plating conditions and modify Li surface. The growth of Li dendrites can be suppressed due to the Li surface strain field under external cell pressure. Also the loss due to dead lithium can be minimized by maintaining a good electrochemical contact between Li deposits. A dendrite-free uniform mossy Li surface with good electrochemical contact will improve the cycling efficiency and safety of the cells.
The effect of external cell pressure was studied in cells with nickel rich LiNi0.6Mn0.2Co0.2O2 cathode and Li metal anode. The cycling performance was analyzed with electrochemical diagnostics tools. The Li surface morphology was characterized with scanning electron microscopy. The effects of various external pressure on cycling efficiency and the Li surface morphology will be illustrated and discussed.

References:

[1] Battery500 Consortium to Spark EV Innovations: Pacific Northwest National Laboratory-led, 5-year $50M effort seeks to almost triple energy stored in electric car batteries, in Office of Technology Transitions Energy.gov (2016).
[2] Gireaud, L., Grugeon, S., Laruelle, S., Yrieix, and B., Tarascon, J. –M., Electrochem. Comm.
8, 1639–1649 (2006)
Rational Design of High Energy Sulfur Cathodes for Lithium-Sulfur Batteries
Authors: Lu Dongping , Shi Lili , Baranovskiy Arthur , Xiao Jie , Zhang Ji-Guang , Liu Jun 
Published: February 2020

Deployment of Lithium-sulfur (Li-S) battery has been hindered by the low practically achievable energy and limited cycle life, although significant advances have been demonstrated in material development and fundamental understandings.1 There are still challenges in pursuing high energy Li-S battery lacking of high energy cathodes, stable anodes and electrolytes, particularly scientific knowledge bridging fundamental research and practical deployment. Sulfur cathodes host active materials for Li+ storage and thus determine the total capacity of the system. However, specific energy of the Li-S battery is highly dependent on the whole weight of the system, of which electrolyte takes a largest weight fraction but contributes nothing to energy. So rational electrode architecture design is of significant importance to not only realize the high sulfur mass loading but also decrease the electrolyte uptake to a very limited level.2 This is very challenging but the only pathway to the target of high energy Li-S battery for practical applications. In an attempt to addressing the key challenges in achieving high energy Li-S battery, our efforts are focused on the understanding of fundamental reasons that affect sulfur utilization in high loading electrodes and with lean amount electrolytes. Based on our understanding, rational cathode design including electrode materials, binders and electrode architectures has been proposed and demonstrated for high loading electrode preparation. At the meeting, we will present our recent progresses on the fundamental understanding and practical demonstration of high energy Li-S batteries.
References
(1) Manthiram A., Fu Y., Chung S.-H., Zu C.,Su Y.-S., Chem. Rev. (Washington, DC, U. S.)
2014, 114, 11751-11787.
(2) Lv D., Zheng J., Li Q., Xie X., Ferrara S., Nie Z., Mehdi L. B., Browning N. D., Zhang J. G.,Graff G. L., Adv. Energy Mater.
2015, 5, 1402290.
Ordered Mesoporous Titanium Nitride As a Promising Carbon-Free Cathode for Aprotic Li-O2 Batteries
Authors: Kim Byung Gon 
Published: February 2020

Despite the extraordinary gravimetric energy densities, Li-O2 batteries are still facing a technological challenge;[1] limited round trip efficiency leading to insufficient cycle life. Recently, carbonaceous electrode materials were found to be one of the primary origins of the limited cycle life,[2] as they produce irreversible side products during discharge. A few investigations based on noncarbonaceous materials have demonstrated largely suppressed accumulation of irreversible side products,[3] but such studies have focused mainly on the materials themselves rather than delicate morphology control. As such, here, we report the synthesis of mesoporous titanium nitride (m-TiN) with a 2D hexagonal structure and large pores (>30 nm), which was templated by a block copolymer with tunable chain lengths, and introduce it as a stable air-cathode backbone. Due to the well-aligned pore structure and decent electric conductivity of TiN, the battery reaction was quite reversible, resulting in robust cycling performance for over 100 cycles under a voltage cutoff condition. Furthermore, by protecting the Li metal with a poreless polyurethane separator[4] and engaging a lithium iodide redox mediator[3], the original capacity was retained for 280 cycles under a consistent capacity condition (430 mAh/g). This study reveals that when the appropriate structure and material choice of the air-cathode are coupled with an advanced separator and an effective solution-phase redox mediator, the cycle lives of Li-O2 batteries can be enhanced dramatically.

Reference
s
:

[1] J. W. Choi, D. Aurbach, Nat. Rev. Mater. 1 (2016) 16013.
[2] M.M. Ottakam Thotiyl, S.A. Freunberger, Z. Peng, P.G. Bruce, J. Am. Chem. Soc.135 (2013) 494−500.
[3] N. Feng, P. He, H. Zhou, Adv. Energy Mater. 6 (2016) 1502303.
[4] B.G. Kim, J. Kim, J. Min, Y. Lee, J.H. Choi, M.C. Jang, S.A. Freunberger, J.W. Choi, Adv. Funct. Mater. 26 (2016) 1747-1756.

Figure 1
Insight into the Relationship between Transition Metal and Anionic Redox As Found in Simple Li-Rich CuO-Li2O Composite Cathode Materials
Authors: Papp Joseph K , McCloskey Bryan D. 
Published: February 2020

Conventional lithium ion battery cathode materials derive their capacity exclusively from transition metal cation redox. Many recent studies on novel Li-rich cathode materials have found substantial reversible anionic redox that shows promise to greatly enhance battery capacity. Unfortunately, this anionic (oxygen) redox contribution to the charge compensation of lithium extraction and insertion typically results in cathode degradation and oxygen gas release. While previous studies have emphasized methods such as the doping of 4d or 5d transition metals to stabilize the formation of peroxo-like species, the mechanism of anionic redox in relation to the transition metals present is still largely unknown.
This study employs simple Li-rich cathode materials as a model for further understanding of the mechanism of anionic redox. Here we have synthesized a number of materials including simple 3d transition metal (e.g., Cu) doped lithium oxide to more closely examine the relationship between oxygen redox and the transition metal present in the cathode material. The materials studied contain a high ratio of lithium to transition metal to probe the maximum anionic redox activity. We will discuss our results in which galvanostatic measurements are combined with quantitative gas evolution analysis, in addition to ex-situ resonant inelastic X-ray scattering and X-ray photoelectron spectroscopy on cycled electrodes, to continue to clarify the required conditions for anionic redox in lithium ion battery cathode materials.
Carbothermal Shock Synthesis of Multimetallic, Solid Solution Electrocatalysts for Air-Based Batteries
Authors: Lacey Steven David , Yao Yonggang , Xu Shaomao , Hu Liangbing 
Published: February 2020

Multicomponent nanomaterials are extremely difficult to synthesize by conventional methods. Accordingly, nanoparticles composed of immiscible elemental combinations tend to phase-separate rather than form singe-phase solid solutions, which limits the compositional space. A synthetic technique that facilitates kinetic control over thermodynamic mixing regimes is therefore advantageous and offers untold scientific and technological opportunities.
Here, we present a general route to alloy up to eight dissimilar elements into high entropy alloy nanoparticles (HEA-NPs) through a facile and tunable synthesis method: carbothermal shock (CTS).1 CTS employs flash heating and cooling of metal precursors on carbon to produce multimetallic nanoparticles with tailored elemental compositions, particle sizes, and structural complexity. Uniform mixing of nearly any metallic combination is achieved through high temperature exposure (~2000 K) during the thermal shock (55 ms) process, while rapid quenching (~105 K/s) retains this high-entropy state to form single-phase solid solutions.
This new synthetic technique promotes materials discovery and design for a wide range of applications, including catalysis and energy storage. Inspired by the performance of quinary HEA-NPs as ammonia oxidation catalysts, novel solid solution nanoparticles (with 2 or more metallic elements) are synthesized and evaluated as electrocatalysts in air-based batteries, such as lithium-oxygen (Li-O2) and Li-CO2. In this way, HEA-NPs composed of catalytically active elements may impart synergistic electrocatalytic effects to improve overall battery performance. This talk will describe the process and underlying mechanism to synthesize HEA-NPs, the overall capabilities of the CTS method, and recent results on electrocatalyst development towards Li-air battery applications.

References:

Y Yao*, Z Huang*, P Xie*, SD Lacey*, RJ Jacob, H Xie, F Chen, A Nie, T Pu, M Rehwoldt, D Yu, MR Zachariah, C Wang, R Shahbazian-Yassar, J Lu and L Hu, “Carbothermal shock synthesis of high-entropy-alloy nanoparticles,” Science, 359 (6383), pp. 1489-1494 (2018).
Intercalation Host Using Defective FePO4-Carbon Composite for Magnesium Rechargeable Battery Cathode
Authors: Orikasa Yuki , Kisu Kazuaki , Iwama Etsuro , Naoi Wako , Yamaguchi Yusuke , Munesada Toshiyuki , Hattori Masashi , Yamamoto Kentaro , Rozier Patrick , Simon Patrice , Naoi Katsuhiko 
Published: February 2020

Magnesium rechargeable batteries are expected as one of candidates for next generation rechargeable batteries. The advantages of magnesium metal anode are the high theoretical capacity, high reserve amount of magnesium metal, and no dendrite formation. However, divalent magnesium ions are hard to diffuse in solid electrodes, and intercalation hosts that can operate at room temperature are limited to Chevrel type structures at present[1].
In this study, we investigated the applicability of FePO4-carbon composite prepared by ultracentrifugation (UC) method as magnesium-ion host structure. For nano-hybrid capacitor electrode, the electrode materials prepared by the UC method reported so far are capable of ultrafast lithium-ion insertion and extraction reaction[2]. Therefore, magnesium-ions could diffuse in the structure with a moderate condition. Since the irreversible magnesium ion insertion-extraction reaction in crystalline olivine type FePO4 has been reported[3], in this study, non-crystalline FePO4 with carbon composite was used.
FePO4-carbon composite was prepared by UC process[2]. The composite was mixed with PTFE. with the weight ratio of 9:1. The electrodes were charged using 1M LiPF6 in a 3:7 volume ratio of ethylene carbonate and diethyl carbonate. The charged electrodes were washed with DME and then, three-electrode cell with an Ag+/Ag double junction reference electrode was assembled. The counter electrode was an active carbon, and the electrolyte was 0.5 M magnesium bis(trifluoromethanesulfonyl)imide in acetonitrile. Charge-discharge measurements were performed at 25oC. The valence state of Fe in the charged / discharged electrodes were examined by X-ray absorption spectroscopy, which was measured in a transmission mode.
Reversible charge / discharge capacity was observed after the first discharge. In operation at 25oC and a rate of 1/20 C, a capacity of apploximately 150 mAh/g and the potential of about 2 V versus magnesium metal are observed. From the TEM-EDX measurements, the structure of FePO4 particles embedded in carbon and the intensity of magnesium is observed only in regions where FePO4 particles exist. X-ray absorption edge at Fe K-edge shifts downward in energy for the discharge reaction, reflecting the reduction of iron ions to maintain electrical neutrality upon magnesium-ion insertion in the discharge reaction.

Reference
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:

[1] D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, E. Levi, Nature
407, 724-727 (2000).
[2] K. Naoi, K. Kisu, E. Iwama, S. Nakashima, Y. Sakai, Y. Orikasa, P. Leone, N. Dupre, T. Brousse, P. Rozier, W. Naoi, P. Simon, Energy Environ. Sci.
9, 2143-2151 (2016).
[3] R. Zhang, C. Ling, ACS Appl. Mater. Interfaces
8, 18018-18026 (2016).