bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combination Technology for Safer Design of Lithium-Ion Batteries
Authors: Senoh Hiroshi , Mukai Takashi , Ikeuchi Yuuta , Yamashita Naoto , Sakamoto Taichi , Tanaka Hideaki 
Published: December 2020

For further penetration of lithium-ion battery, safer battery design with high energy density is required. In the case of the thermal runaway of conventional lithium-ion batteries, the reaction of electrolyte on the surface of graphite anode at higher temperature causes the gas generation with the temperature rise. Subsequently, the short circuit due to the separator meltdown leads to the oxygen release by the pyrolysis of cathode and the thermite reaction above the melting of aluminum utilized for the current collector and the cell package. The construction of novel safer battery systems with high energy density is possible through a judicious choice of each component: cathode material, electrolyte, separator, anode material, current collector and package.
We develop safer battery configurations through the analysis of practical batteries using various techniques such as calorimetry and overcharge / internal short-circuit tests. In this study, we assemble 1 Ah class pouch-type full cell with lithium iron phosphate cathode and silicon oxide anode [1]. The full cell shows good charge-discharge properties even at high-rate and 100˚C (Figure 1). On the estimation, however, the electrochemical energy of both electrode active materials is only about 3% of the total thermal energy of full cell. Thus, we replace aluminum with stainless steel utilized for the current collector and package. In addition, we select a separator of heat-stable nonwoven fabric instead of polyethylene/polypropylene. The total thermal energy of full cell by the alternative separator, current collector and package is found to be reduced to 14% of the initial value. In short-circuit testing, the full cell did not show fire though heat and smoke were generated since the maximum temperature of the cell is only 52˚C.
In this way, it is possible to design batteries with highly safe by considering the non-flammability of each component such as the current collector and the package as well as the separator.
References
[1] M. Yanagida, T. Mukai, Y. Ikeuchi, N. Yamashita, T. Sakamoto, H. Senoh and H. Tanaka, Abstract of the 60th Battery Symposium in Japan, 2B23 (2019).

Figure 1
Gas Generation Evaluation of Lib in Case of Thermal Runaway Reaction
Authors: Okada Ken , Shibata Tsuyoshi , Saito Yoshiyasu 
Published: December 2020

In recent years, lithium-ion batteries (LIB) have advanced in performance and capacity, and their applications to electric vehicles, next-generation mobility, mobile devices, etc. are expanding. However, LIB may be ignited or exploded due to external stimuli such as short circuit, impact, heating, etc., and the number of accidents of ignition or explosion is increasing with the expansion of these applications and the increase of energy density.
In this study, we investigate the case where the external environmental temperature of LIB rises, and the reaction runaway occurs. As an item of safety evaluation, the purpose is to establish a method for measuring the temperature rise and pressure rise of a battery and evaluating the amount of reaction product gas and the gas composition. If the amount of gas generated is known in advance, it can be used for studying protective measures and designing closed containers for safety tests.
In the experiment, the 20L closed chamber used for the explosive experiment was modified and used for LIB experiment. A LIB with electric heater were introduced into the explosion chamber and the behavior of runaway reaction was observed, monitoring the terminal voltage, internal pressure, and temperature. Further, after the test, the gas was sampled, and the amount of gas was estimated and the gas composition was analyzed. We also compared the results of two LIBs with SOC (State of Charge) of 0% and 95%.
As a result, the following findings were obtained. (1) An experimental system was developed to evaluate the amount of the gas without leakage causing the thermal runaway while monitoring the LIB temperature, voltage, and pressure inside the container. (2) It was found that the LIB temperature reached ~ 1200 ° C (SOC 95%) and ~ 600 ° C (SOC 0%) during the runaway reaction. (3) The amount of gas during the runaway reaction is 141 to 152L (SOC 95%), 72L (SOC 0%), and special attention should be paid to the gas generation when the LIB is charged completely. (4) The gas after the runaway reaction contains about 30% carbon monoxide, 15% hydrogen, 26% hydrocarbon (SOC 0%), 50% (SOC 0%). We should pay attention to the CO poisoning, backdraft, and flash.

Figure 1
(Invited) Stress Evolution on the Solid Electrolyte in Lower Temperature Operating Planar Sodium Nickel Chloride Batteries
Authors: Yang Choongmo , Park Yoon-Cheol , Moon Jiwoong , Kwon Ohmin , Park Inchul , Kim Yeongwoo , Kim Hwa-Jung , Choi Hanul , Lee Younki , Jung Keeyoung 
Published: December 2020

Sodium nickel chloride (Na-NiCl2) battery is one of the most promising candidates as a large scale electrochemical energy storage device since it offers high safety, long lifetime, and high energy density. The battery comprises molten metallic Na and NiCl2 as negative and positive electrodes, respectively, separating them by a β”-Al2O3–family solid electrolyte (BASE). In order to facilitate fast sodium-ion transport in the cathode compartment, the battery typically operates at 300oC accompanying with molten NaAlCl4 (catholyte), which is infiltrated into the cathode materials powder. A drawback of the efficient battery hampering broader market penetration is high manufacturing cost as it adopts expensive heterogeneous sealing technologies, such as thermal compression bonding, glass sealing, and laser beam welding, which are inevitable to withstand its high operating temperature. However, when lowering the operating temperature down to below 200oC, inexpensive polymer can be introduced replacing all the expensive sealing technologies, through which cell manufacturing process can be substantially simplified at the same time.
In developing the lower temperature operating planar Na-NiCl2 battery, one of the major cell failure modes is mechanical failure in solid electrolytes either by thermal stress accumulation upon freeze-thaw cycles or by stresses developed by pressure difference between cathode and anode compartments during charge-discharge cycles. The presentation will start with defining failure modes of this new class of Na beta-alumina battery with special emphasis on electrolyte failure. In order to understand the stress accumulation in the vicinity of the solid electrolyte, a set of finite element analyses (FEA) has been conducted for various simulated conditions. It turns out that (1) sealing temperature, and (2) inner volumes of cathode and anode compartments need to be carefully designed to avoid the mechanical failure. The results of the calculation and cell design strategy for this novel battery will be discussed.

Figure 1
Visible Light Photocatalyst Prepared from Active Organic Photovoltaic Cell
Authors: Nagai Keiji , Kuwabara Takayuki , Ahmad Mohd Fairus , Nakano Masahiro , Karakawa Makoto , Taima Tetsuya , Takahashi Koushin , Abe Toshiyuki 
Published: December 2020

The organic photovoltaic devices (OPVs) have potential in low-cost, large-area printing routes with high efficiency owing to the variety of organic materials. The active layer has a role to absorb photon and convert to electrostatic energy of separated electron and hole pair. If the separated charge in its active layer can be utilized to chemical reaction directly without collecting by electrodes, it would be a simple device for photoenergy conversion and has a great merit to use the photon energy. Here we introduce an large negative threshold potential of −0.35 V vs. Ag/AgCl by the use of ZnPc/PCBM:P3HT/ZnO electrode, which was prepared by removing PEDOT:PSS/Au electrode of an inverted OPV device [1] and coating with ZnPc. A co-photocatalysis property of ZnPc was observed in the photoelectrochemistry and scanning Kelvin probe microscopy.
From the mother OPV, the gold electrode was removed mechanically and ZnPc was coated by vapor deposition. The detailed experimental conditions and characterizations of the electrode are shown in Ref [2].
Fig. shows voltammograms in a thiol solution for the BHJ electrode (a) and the ZnPc coated BHJ electrode (b). The photoanodic current (red) for the electrode with ZnPc (b) was much larger than that without ZnPc (a). For the ZnPc coated BHJ electrode with ZnO, the threshold potential of the photoanodic current was around −0.35 V vs. Ag/AgCl. On the other hand, for the ZnPc coated BHJ electrode without ZnO, the threshold potential of the photoanodic current was around −0.0 V vs. Ag/AgCl as shown in our previous paper [3]. The present larger gain than that without ZnO would be due to the effect of ZnO as a hole blocking layer. The threshold value of −0.35 V vs. Ag/AgCl was almost equal to the conduction band edge potential of ZnO, that is, the photogenerated electrons in the BHJ active layer can preferentially transfer to ZnO when the anodic polarization of ITO was deeper than the ZnO edge. Note that the ZnPc electrode exhibited an anodic current in the dark with the threshold potential of +0.25 V vs. Ag/AgCl, that is, the ZnPc can function as a catalyst of 2-mercaptoethanol oxidation. The large anodic photocurrent may be caused by such a catalytic function of ZnPc.
References

T. Kuwabara, et al., Sol. Energy Mater. Sol. Cells, 2008, 92, 1476.

K. Nagai, et al., Chem. Commun. 2019, 55, 12491.

T. Abe, et al. Chem. Phys. Lett., 2012, 549, 77.

M.-F. Ahmad, et al. NPG Asia Mater., 2018, 10, 630.

Figure 1
Room Temperature Synthesis of Ordered Intermetallic Electrocatalysts
Authors: Hall Shoji 
Published: December 2020

The conversion of O2 to H2O is an important fuel cell reaction for the recovery of renewable electricity from chemical fuels. Alloys of Pt-group metals (PGMs) with transition metals have emerged as catalysts with enhanced activity and durability for the oxygen reduction reaction (ORR). To date, most studies focus exclusively on alloys that adopt a Face-centered cubic (FCC) or Face-centered tetragonal (FCT) crystal lattice. Under ORR operating conditions, these materials evolve from alloys to Pt core-alloy shell materials, in this case both the alloy core and Pt shell retains the FCC or FCT type crystal structure; indicating that materials can dynamically change during catalysis.
Here we present the synthesis of Pd-Bi based ordered intermetallics by partial dealloying of a Bi rich alloy. We found that under ORR operation conditions, β-PdBi2 (I4/mmm space group) which adopts a tetragonal lattice, transforms to α-Pd3Bi (Pmma space group) which adopts an orthorhombic crystal structure; this transformation is mediated by oxidative Bi corrosion under potential cycling, and reconstruction of the atoms in the bulk. To the best of our knowledge, this is the first report of a material that exhibits an electrochemically driven, non-congruent phase transition among materials with different crystal structures. The resulting phase-converted Pd3Bi is stable and exhibits high performance for ORR. Phase-converted Pd3Bi outperform Pt and Pd metal, reaching mass activities of 2.6 A/mgPd, which is nearly 10X higher than Pt/C (~0.3 A/mgPt) and Pd/C (~0.2 A/mg) at 0.9 V vs the Real Hydrogen Electrode (RHE). The mass activity of Pd3Bi decreases by ~38% after 10,000 cycles, indicating that it is stable. Activation energy (Ea) determined by temperature dependent electro-kinetic measurements indicates that the activity enhancement on phase-converted Pd3Bi originates from anion-poisoning resistant behavior. These results establish that PGMs-based ordered intermetallics with low-symmetry crystal structures can be highly active and durable electrocatalysts.
(Invited) Mechanism of a Sensitized Thermal Cell
Authors: Matsushita Sachiko 
Published: December 2020

Efficient and low-cost thermal energy-harvesting systems are crucial to solve the global energy problem. A new energy conversion system for the generation of electric power directly from heat energy is described herein. The device is a sensitized thermal cell (STC) based on a dye-sensitized solar cell. In the established system, thermally-excited electrons in a semiconductor were utilized instead of photon-excited electrons in a dye. Consequently, the STC generated electricity by “placing” or “burying” the cell in the heat source.
To prove the concept, first, we examined the redox ability of thermally excited electrons (Mater. Horiz., 2017, 4, 649–656.). Next, we demonstrated that the semiconductor-sensitized solar cell can generate electric power by thermally excitation (ACS Applied Energy Materials, 2019, 2, 13–18.; J. Phys. Chem. C, 123, 2019, 12135-12141.). Lastly, we performed the long-time power generation at 80 degree using STC and observed the end; and surprisingly found that the battery characteristics were restored after discharging by placing or burying the battery in a heat source ( J. Mater. Chem. A, 2019, 7, 18249-18256.). Additinally, we show that the open circuit voltage of STC has the Fermi level dependnce of the semiconductor electrode (Chem. Lett. in press). In the presentation, these recent results were summarized and the difference between photo excitation and thermally excitation will be discussed..
Effect of the Fe/Co Ratio on Electrocatalytic OER Activity of Cofe-LDH
Authors: Hemmi Shota , Takashima Toshihiro , Irie Hiroshi 
Published: December 2020

Solar hydrogen production through photocatalytic or photoelectrochemical water splitting has been considered as a promising route for overcoming the current global reliance on fossil fuels. Within these processes, oxygen evolution reaction requires a large overpotential due to its slow reaction kinetics. Therefore, achievement of efficient OER catalysis using abundant elements has been highly demanding challenge and understanding of the reaction mechanism of OER is important for a rational design of active catalysts. Recently, we identified that Fe4+ acts as an intermediate species of OER on α-Fe2O3, and its efficient formation was found to be necessary to lower the overpotential [1]. Meanwhile, Fe ions incorporated into Ni and Co hydroxides have been reported to be oxidized to Fe4+ during electrochemical anodization [2],[3], and efficient OER has been demonstrated using NiFe and CoFe layered double hydroxides (LDHs) [4]. In this study, we studied the effect of Fe addition on electrical property and OER activity of CoFe-LDH.
CoFe-LDH with different ratio of Co and Fe was synthesized on FTO substrate using hydrothermal method, and its formation was confirmed by XRD measurements. Figure shows chrono amperograms of CoFe-LDH measured at alkaline conditions. As the ratio of Fe was increased up to 36%, a gradual improvement in current density and a negative shift in the onset potential were observed although further increase in Fe content was detrimental for OER activity. Notably, all the CoFe-LDH showed higher OER activity compared with both monometallic Co and Fe oxyhydroxide, indicating that coexistence of Co and Fe is beneficial for the catalyst performance. Details will be discussed in the conference.
Reference
[1] T. Takashima, K. Ishikawa, H. Irie, J. Phys. Chem, 2016, 120, 24827
[2] Hans Christian Bruun Hamen, Christian Bender Koch, Inorg. Chem, 1994, 33, 5363-5365
[3] G. Rajeshkhanna, Thangjam Ibomcha Singh, Nam Hoon Kim, Joong Hee Lee, ACS Appl. Mater. Interfaces, 2018, 10, 42453-42468

Figure 1
In-Situ Soft X-Ray Spectromicroscopy Characterization of Electrochemical Processes
Authors: Zhang Chunyang , Ingino Pablo , Obst Martin , Shahcheraghi Ladan , Yuan Hao , Eraky Haytham , Wang Jian , Higgins Drew , Hitchcock Adam P. 
Published: December 2020

Soft X-ray Scanning Transmission X-ray microscopy (STXM) is a synchrotron-based technique which can provide both spectroscopic characterization (near edge X-ray absorption fine structure, NEXAFS) and chemically selective imaging with high spatial resolution (~30 nm). Recently, we have developed in situ flow electrochemical devices [1,2] which allow control of the electrochemical environment while conducting STXM measurements, thus providing a platform for in-situ studies of electrochemical oxidation and reduction processes. This presentation reports results of in situ flow electrochemical STXM studies on three different systems to demonstrate the present capabilities. First, the ability to rapidly exchange the electrolyte is demonstrated by a STXM Fe 2p and in situ electrochemical study of the ferro/ferricyanide solution redox system. Second Cu and Ag-doped Cu catalysts for CO2 electrochemical reduction (CO2R) were successfully prepared using in situ electrodeposition. Third, the electrolyte was changed from CuSO4 to NaHCO3 (as substrate for CO2R) and the cell was operated under electrochemical CO2 reduction conditions, while monitoring the changes to the Cu deposited layer at various potentials, including –0.5 V where CO2 reduction is expected [3]. The figure shows a cyclic voltammogram (CV) and color-coded Cu oxidation state maps which were derived from Cu 2p stacks measured under chronoamperometric conditions at the indicated potentials. These results demonstrate that in situ flow electrochemical STXM measurements can be performed in our device under varying electrochemical reaction conditions, enabling visualization of the morphology changes from selective energy imaging, and quantitative tracking of electrochemical transformations from spectromicroscopy. This system will be used for in situ studies of CO2 electrochemical reduction catalysis with the goal of obtaining mechanistic insights to guide the development of catalysts with improved efficiency and selectivity. In addition, the system will be used to study a variety of material science, chemistry and environmental science related questions associated with oxidation or reduction processes, such as mechanisms of extra-cellular electron transport in marine sediment microbial biofilms [4].
This research is supported by NSERC (Canada). STXM measurements were performed at the ambient STXM facility at the Canadian Light Source, which is funded by the Canadian Foundation for Innovation.
[1] V. Prabu et al., Rev. Sci. Inst. 89 (2018) 063702.
[2] P. Ingino, et al., in preparation
[3] L. Wang, D.C. Higgins, et al., Proc. Nat. Acad. Sci. (2020) 01821683. DOI: 10.1073/pnas.1821683117
[4] M. Obst, et al., Microsc. Microanal. 24 (S-2) (2018) 502-504.

Figure 1
In-Situ Electrochemical Mapping of Lithium-Sulfur Battery Interfaces Using AFM-SECM
Authors: Mahankali Kiran , Thangavel Naresh kumar , Arava Leela Mohana Reddy 
Published: December 2020

Although lithium-sulfur (Li-S) batteries hold significant promise as the next-generation technology to replace lithium-ion batteries, their development is still hampered by several challenges such as rapid capacity fade, short cycle life, and poor coulombic efficiency(1, 2). To address these issues, extensive research efforts were devoted to finding better electrode and electrolyte materials. However, only a limited emphasis was given towards understanding the true nature of lithium polysulfides (LiPS) interactions at the electrode/electrolyte interface mainly due to the nonexistence of a comprehensive tool to grasp the working mechanism in real-time. While much of the in-situ studies envisage the nature of LiPS reactivity along with their chemical identity in different electrolytes(3-6), a detailed temporal and spatial mapping of LiPS interactions on the electrode surface is not explored much(7, 8).
Herein, we introduce the atomic-force-microscopy-based scanning electrochemical microscopy (AFM−SECM) technique to study the Li−S interfacial redox reactions at nanoscale spatial resolution in real-time. In situ electrochemical mapping of the discharge end products during oxidation revealed heterogeneity in the particle’s electrochemical activity and spectroscopic evidence demonstrated the presence of Li2S and Li2S2 species. During charging, Li2S2 was found to undergo facile oxidation compared to Li2S to produce intermediate LiPS. Subsequently, the unoxidized Li2S chemically/electrochemically reacts with the intermediate LiPS. At higher oxidation potentials, the as-reacted LiPS turns into insulating products, which accumulate over cycling, resulting in the reduction of active material utilization and ultimately leading to capacity fade. The interdependence of the topography and electrochemical oxidative behavior of Li2S on the carbon surface by AFM−SECM reveals the Li2S morphology−activity relationship and provides new insights into the capacity fading mechanism in Li−S batteries.

References:

(1) Xu, I. Belharouak, X. Zhang, R. Chamoun, C. Yu, Y. Ren, A. Nie, R. Shahbazian-Yassar, J. Lu and J. C. Li, ACS Appl. Mater. Interface., 6, 21938 (2014).
(2) Xu, J. Lu and K. Amine, Adv. Energy. Mater., 5 (2015).
(3) L. Wu, L. A. Huff and A. A. Gewirth, ACS Appl. Mater. Interfaces., 7, 1709 (2015).
(4) Barchasz, F. Molton, C. Duboc, J. C. Lepretre, S. Patoux and F. Alloin, Anal. Chem., 84, 3973 (2012).
(5) Zhang, Z. W. Zhang, H. J. Peng, J. Q. Huang and Q. Zhang, Small Methods, 1, 1700134 (2017).
(6) Liu, G. Zhou, A. Yang, X. Yu, F. Shi, J. Sun, J. Zhang, B. Liu, C. L. Wu and X. Tao, Proc. Nat. Acad. Sci., 116, 765 (2019).
(7) Ji and L. F. Nazar, J. Mater. Chem., 20, 9821 (2010).
(8) Manthiram, Y. Fu, S. H. Chung, C. Zu and Y. S. Su, Chem. Rev., 114, 11751 (2014).