bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nano-Thin TiO2 Layer Coating By Polydopamine Pre-Coating for Highly Stable Ni-Rich Layered Oxides with 4.5 V High-Voltage Operation in Lithium-Ion Batteries
Authors: Kim Hyeongwoo , Jang Jihye , Byun Dongjin , Choi Wonchang , Kim Hyungseok 
Published: December 2020

As the demand for electric vehicles or large-scale energy storage system increases rapidly, high-energy and stable lithium-ion batteries (LIBs) have been required. Accordingly, a large attention has been paid to Ni-rich layered oxides which has a higher energy density than LiCoO2, and the Ni-rich layered oxides have been applied to cathode materials for LIBs. Although the researchers succeeded in obtaining high reversible capacity by increasing the Ni content, the higher Ni content in layered oxides is still structurally unstable, which seriously degrades the cycling stability and lefts many questions on a reliability of the LIBs. Generally, the cycle degradation is mainly related to surface degradations which can be ascribed to side-reaction products and NiO formation from the oxidation of the electrolyte, and these are caused by the generation of highly reactive Ni4+ ions during charging to high-voltage (≥4.3 V). These surface degradations are accelerated when the cell is operated at high temperature, those side reactions at the electrode/electrolyte interface and structural degradation are seriously worsen. To solve the problem, coating strategy is effective way to mitigate the surface degradation, and the uniformly coated layer can can suppress the side reaction effectively for each particle. However, conventional coating methods such as ball-milling or wet coating have a limitation to achieve the uniformity of the coating layer due to the lack of the driving force for making the coating material concentrated on the whole surface.
In this study, a stable Ti-based oxide coating layer is introduced on LiNi0.6Co0.2Mn0.2O2 (NCM). To obtain a nano-thin uniform coating layer based on the driving force, concentrating the coating material, we coated the polydopamine (PDA) on the NCM first to trap Ti4+ ions on the surface in the coating solution through forming O-H catechol groups. This helps to attract Ti(OEt)4 molecules to the NCM surface, thus uniform TiO2 nanolayer can be obtained after the calcination process. The TiO2 nanolayer suppresses side reactions with the electrolyte generated during the charging process to improve the surface stability. We confirmed the growth of CEI (cathode electrolyte interphase) layer originated from side reactions during the cycling through XPS and TEM analyses Consequently, it enhances the cycling stability in the high-voltage operation (4.5 V), and it also improves the high temperature (60 oC) cycling. In summary, this talk will give a facile way to form a uniform and ultrathin TiO2 nanolayer on Ni-rich oxide surface by pre-coating a polydopamine layer. We expect that the PDA pre-coating method is effective and could be applied to other fields where high-quality coating is required.

Figure 1
Novel Bulky Lithium Salts and Their Electrolytes for Safer Solid-State Lithium Metal Battery
Authors: Nguyen Thi Khanh Ly , Yver Clémence , Devaux Didier , Alloin Fannie , Gigmes Didier , Phan Trang N.T. , Bouchet Renaud 
Published: December 2020

In recent years, Lithium metal batteries (LMBs) have gained great interests thanks to their high capacity that can respond to the continuous increasing need for energy storage and device. The design and development of new solid-state electrolytes e.g. polymer based ones (SPEs) then became crucial towards intrinsically safer LMBs. A successful electrolyte candidate needs to fulfill several requirements such as high transference number (tLi
+) and a compromise between two antagonist properties: conductivity and mechanical properties. Most researches focused on the synthesis of single-ion conducting electrolytes as a strategy to overcome these difficulties1,2. However, these materials often require complicated and delicate chemistry and their conductivity often remains low (σ < 10-5 S/cm at 60°C). An alternative promising route that received much less attention is the development of bulky Lithium salts with macroanion. The bulky anion reduces ion paring and salts aggregation and present negligible mobility compared to Lithium cation resulting in higher transference number3.
In this work, we present a new macroanion based on Polyhedral Oligomeric Silsesquioxane (POSS) grafted with either polyethylene oxide oligomers (PEG) and/or Lithium sulfonyl (trifluoromethanesulfonyl) imide (LiTFSI) denoted as POSS-LiTFSI-PEG or POSS-LiTFSI respectively. Thus, SPE has been prepared with a reference high molecular weight polyethylene oxide at different OE/Li ratio from 10 to 25. This new concept of bulky multi-anion based on TFSI moieties allows a complete salt dissociation, an enhancement of the mechanical properties thanks to the presence of the inorganic POSS multi anions that play the role of nano fillers, and finally, a strong increase of the Li+ transference number (tLi+>0,55), which opens many perspectives. The cycling performance obtained in both Lithium symmetric cells and LMBs prototypes will be also presented.
References
(1) Bouchet, R.; Maria, S.; Meziane, R.; Aboulaich, A.; Lienafa, L.; Bonnet, J.-P. P.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Devaux, D.; et al. Single-Ion BAB Triblock Copolymers as Highly Efficient Electrolytes for Lithium-Metal Batteries. Nat. Mater.
2013, 12 (5), 452–457.
(2) Zhang, H.; Li, C.; Piszcz, M.; Coya, E.; Rojo, T.; Rodriguez-Martinez, L. M.; Armand, M.; Zhou, Z. Single Lithium-Ion Conducting Solid Polymer Electrolytes: Advances and Perspectives. Chem. Soc. Rev.
2017, 46 (3), 797–815.
(3) Chinnam, P. R.; Wunder, S. L. Polyoctahedral Silsesquioxane-Nanoparticle Electrolytes for Lithium Batteries: POSS-Lithium Salts and POSS-PEGs. Chem. Mater.
2011, 23 (23), 5111–5121.

Figure 1
Investigation of a Novel Bi-Functional Additive for High Voltage LiNi1.5Mn0.5O4/Graphite Cells
Authors: Kim Jongjung , Adiraju Venkata Aditya Kiran , Rodrigo Nuwanthi dilhari , Hoffmann Jennifer , Payne Martin , Lucht Brett L. 
Published: December 2020

LiNi1.5Mn0.5O4 (LNMO)/graphite (Gr) cells are a promising candidate for commercial Li-ion batteries due to their high power density and low costs. However, the most challenging obstacle of LNMO/Gr cell is severe capacity fading at high temperature.1 The severe cell failure is associated with transition metal ion dissolution (Ni and Mn) from the positive electrode caused by acidic species, such as hydrogen fluoride, which is generated through the hydrolysis of lithium hexafluorophosphate by residual water in the electrolyte solution.2 The dissolved metal ions migrate through the electrolyte solution and deposit at the anode, where they cause a continuing deterioration and reformation of the solid electrolyte interphase,which results in an increasedcell resistance and steadily decreasing capacity utilization.
To suppress these issues, a novel bi-functional electrolyte solution additive has been synthesized and tested. LNMO/Gr cells containing the additive display a significantly improved capacity retention during high temperature cycling. The end-of-test of the harvested electrodes analysis indicates that the additive may act as HF scavenger and as film-forming agent on the graphite electrode.

Experiments

The 2032-type coin cells were fabricated with LNMO, graphite, separators (Celgard 2325, GF/D), and electrolytes. The standard electrolyte formulation is 1.2 M LiPF6 EC:PC:DEC=15:20:65 (v/v/v). The cells were pre-cycled five times at room temperature, followed by cycled seven times for the rate testing. And then, the cells were cycled for 100 cycles at 3.3-4.9V with a rate of 1 C at 45 ℃. Constant voltage steps were applied at the end of charge with 0.05 C cut-off.

Reference

D. Lu, M. Xu, L. Zhou, A. Garsuch, and B. L. Lucht, J. Electrochem. Soc., 160, A3138–A3143 (2013).

N. P. W. Pieczonka, Z. Liu, P. Lu, K. L. Olson, J. Moote, B. R. Powell, J. Kim, J. Phys. Chem. C, 117, 15947–15957 (2013).

Figure
1 (a) The discharge capacity and (b) capacity retention of LNMO/Gr cells at 45oC.

Figure 1
Application of Artificial Interphase on Ni-Rich Cathode Materials in All Solid State Li-Ion Batteries
Authors: Liao Cheng-Hung , Jeng Ru-Jong , Wu Nae-Lih (Nick) 
Published: December 2020

Among many cathode materials, nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM 811) has been spotlighted as one of the most feasible candidates for next-generation LIBs because of its high discharge capacity (~200 mAh/g). However, NCM 811 shows significant performance degradation, which is mostly attributed to cation mixing, surface side reactions, and intrinsic structural instability originating from the large volume changes during repeated cycling.
Conventional lithium ion batteries (LIB) normally use flammable nonaqueous liquid electrolytes, resulting in a serious safety issue in use. In this respect, all solid state lithium ion batteries (SSLIBs) are regarded as a fundamental solution to address the safety issue by using a solid state electrolyte (SSE) in place of the conventional liquid one.
This study assess the performance of NCM811 cathode for all-solid-state batteries based on hybrid PEO-ceramic solid electrolyte. Artificial CEI coating layer has been developed in order to prevent direct contact of electrolyte with the cathode, thus avoid the negative effects, such as side reactions, on NCM 811. The incorporation of ceramic materials results composite electrolytes, containing inert fillers, offer improved mechanical stability under high operating temperature.
It is demonstrated that the polymer of hybrid electrolytes can penetrate into cathode, providing a good Li+ transfer channel inside the battery under high operating temperature. Moreover, the protective coating on NCM811 effectively improve the electrochemical stability.
(This work is supported by Ministry of Science and Technology, Taiwan under contract number: MOST 108-3116-F002-008)
Interfacial Potentials in a Thin Film All-Solid-State Li-Ion Battery Probed By in Operando KPFM
Authors: Strelcov Evgheni , Fuller Elliot James , Weaver Jamie Lynn , Swift Michael , Kolmakov Andrei , Zhitenev Nikolai , Qi Yue , McClelland Jabez J. , Dura Joseph A. , Talin A. Alec 
Published: December 2020

Designing smaller, safer, cheaper, and more stable batteries necessitates thorough understanding of the electrochemical processes governing their operation at multiple length scales. In all-solid-state power sources the electrolyte is no-flammable and can be made ultimately thin, making them safer and more compact. Yet, experimental evidence suggests that the multiple internal interfaces in their layered structure give rise to high impedances, limiting their performance. Studying these nanoscopic interfaces requires microscopic tools. Here, we employ in operando Kelvin Probe Force Microscopy (KPFM) to quantitatively measure the potential distribution in a solid-state Li-ion battery as a function of its state of charge. The battery was fabricated by sequentially depositing thin layers of Pt (110-130 nm), LiCoO2 (280-420 nm), LIPON (1100-1200 nm), Si (50-240 nm) Cu or Pt (150-200 nm) onto a Si/SiO2 wafer (oxide thickness 100 nm). The fabricated battery was cleaved in an Ar atmosphere to expose the stacked layers, mounted on a holder, wired, and safely transferred without exposing to air into a dual-beam instrument that combines a scanning electron microscope (SEM), a Ga-ion focused ion beam (FIB) and an atomic force microscope (AFM) in one vacuum chamber (residual pressure of 10-4 Pa). The stacked battery was milled to expose a cross-section of the layers, and imaged using SEM and KPFM, while cycling the battery. The acquired potential maps reveal a highly non-uniform interelectrode potential distribution, with most of the potential drop occurring at the electrolyte-Si anode interface in the pristine battery. During the first charge, the potential distribution gradually changes, revealing complex polarization within the LIPON layer due to Li-ion redistribution. Cycling the battery at high rate significantly decreased its capacity, although the capacity loss can be recovered. KPFM imaging allowed the detection of the interface responsible for this capacity loss. Li distribution in the battery was also measured using Neutron Depth Profiling as a function of the state of charge. The acquired data was compared to first principles calculations shedding light onto the interfacial Li-ion transport in the battery and its reversibility.
ES acknowledges support under the Cooperative Research Agreement between the University of Maryland and the National Institute of Standards and Technology Center for Nanoscale Science and Technology, Award 70NANB14H209, through the University of Maryland.
Pore Network Modeling of Microporous Layers for Polymer Electrolyte Fuel Cells
Authors: Shintaro Iwasaki , Nakajima Hironori , Kitahara Tatsumi 
Published: December 2020

Liquid water accumulated in the catalyst layer (CL) and gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC, PEMFC) results in performance deterioration due to inhibition of oxygen transport to the cathode CL (Flooding). To enhance the drainage in the GDL, the application of a microporous layer (MPL) is effective to the CL side of the GDL substrate [1, 2]. To elucidate the effects of two-phase flow on the oxygen transport in an MPL for its optimized designs, we model three dimensional porous structures of in-house MPLs with pore network model (PNM) [3, 4] for convective air permeation and oxygen diffusion. Pore diameter distribution derived by a focused ion beam scanning electron microscope (FIB-SEM) is employed in the PNM. Air permeation measurements combined with oxygen diffusion measurements with changing wetting liquid saturation (Galwick, Porous Materials Inc., USA) by using gas chromatography validate the model.
Acknowledgments
The authors are indebted to graduate students, Messrs. Yuhang Liu, Kentaro Harano, Dingfeng Chen for help in the modeling and experiment. Thanks are offered to Professor Kohei Ito of Kyushu University for valuable discussions. The authors acknowledge Ms. Chie Uryu of International Research Center for Hydrogen Energy, Kyushu University for operating the FIB-SEM.
References

Nakajima H, Konomi T and Kitahara T. 2007. Direct water balance analysis on a polymer electrolyte fuel cell (PEFC): Effects of hydrophobic treatment and micro-porous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation. Journal of Power Sources 171: 457-463.

Kitahara T, Konomi T and Nakajima H. 2010. Microporous layer coated gas diffusion layers for enhanced performance of polymer electrolyte fuel cells. Journal of Power Sources 195: 2202-2211.

Gostick J, Aghighi M, Hinebaugh J, Tranter T, Hoeh MA, Day H, Spellacy B, Sharqawy MH, Bazylak A, Burns A, Lehnert W and Putz A. 2016. OpenPNM: A pore network modeling package. Computing in Science & Engineering 18: 60-74.

http://openpnm.org/. Accessed on September 14, 2020
Digital Processing of the Different Operating Modes of a PEM Electrolyser Viafast Camera
Authors: Rohe Julien , Lin Kwong Chon Christophe , Boulevard Sebastien , Damour Cedric , Grondin-Perez Brigitte , Kadjo Jean-Jacques Amangoua , Bessafi Miloud 
Published: December 2020

One way of increasing the efficiency of the polymer electrolyte membrane is to study two-phase flow effects in order to improve the evacuation of the product of the reaction, namely the water in fuel cells [1] and the dioxygen in the electrolyser [2]. The analysis of the water evacuation in PEMFC has been studied extensively [3], but the formation and the evacuation of dioxygen in PEMWE are not yet systematic. We propose to detect water bubbles through 3 actions in order to observe and identify dioxygen bubbles. Firstly, the image segmentation via morphological processing to create a sketchily data set. This approach has some limits, such as size or shape detection. Therefore, for a second stage a training of a shape regression convolutional neural network is used to estimate shape and complex forms [4]. And finally, the last action a validation of the neural model in online and real-time is provided. We hope that this work will help further studies, allowing to link shape, frequency, residence time, and velocity of bubbles of the different parameters used with electrolyser.
Figure 1: Detection and regression shape of dioxygen bubble through CNN
REFERENCES
1. Y. Ding, X.T. Bi, D.P. Wilkinson, Numerical investigation of the impact of two-phase flow maldistribution on PEM fuel cell performance, International Journal of Hydrogen Energy, Volume 39, Issue 1, 2014
2. F. Aubras, J. Deseure, J.-J.A. Kadjo, I. Dedigama, J. Majasan, B. Grondin-Perez, J.-P. Chabriat, D.J.L. Brett,Two-dimensional model of low-pressure PEM electrolyser: Two-phase flow regime, electrochemical modelling and experimental validation,International Journal of Hydrogen Energy,Volume 42, Issue 42,2017, Pages 26203-26216.
3. J.G. Carton, V. Lawlor, A.G. Olabi, C. Hochenauer, G. Zauner, Water droplet accumulation and motion in PEM (Proton Exchange Membrane) fuel cell mini-channels, Energy, Volume 39, Issue 1, 2012
4. Tim Haas, Christian Schubert, Moritz Eickhoff, Herbert Pfeifer, BubCNN: Bubble detection using Faster RCNN and shape regression network, Chemical Engineering Science, Volume 216, 2020.
Keywords: PEMWE, high-speed camera, bubble gas tracking, CNN, segmentation

Figure 1
Fast Charge Transfer between LLZO Solid Electrolyte and LCO Cathode Thin Films with a Modified Interface
Authors: Sastre Jordi , Chen Xubin , Aribia Abdessalem , Tiwari Ayodhya N. , Romanyuk Yaroslav E. 
Published: December 2020

Thin film deposition of solid electrolytes can be useful for the fabrication of better solid-state batteries by reducing the thickness of the electrolyte material to a few hundred nanometers. This facilitates ionic conductance for faster charge-discharge and reduces the total volume of inactive material, therefore increasing energy and power density. Thin film batteries can also be valuable model systems to investigate interface charge dynamics and to serve as playgrounds for interface engineering, without the complexity of bulk systems. Here we investigate the charge transfer properties between the lithium garnet Li7La3Zr2O12 (LLZO) solid electrolyte and the LiCoO2 cathode using a thin-film model system, with the aim of reducing the interface resistance and allowing high charge-discharge rates.
Bulk LLZO electrolyte has come under the spotlight owing to its high ionic conductivities (10-4 - 10-3 S/cm) as well as a wide electrochemical stability window (against metallic lithium anode and high potential cathode materials). We developed a method for fabricating crystalline LLZO thin films using magnetron co-sputtering followed by an annealing step at 700°C (significantly below the standard processing temperatures). The resulting 500 nm-thick Ga-doped LLZO thin films show densities and ionic conductivities (2×10-4 S/cm) comparable to the values observed in bulk ceramic pellets.[1]
Based on this thin film fabrication process, we fabricated an all-thin-film model system to investigate the LLZO / LCO cathode interface. This architecture provides an easy access to the interface for characterization, allowing one to identify the degradation processes taking place at the interface under high-temperature co-sintering. Introducing an in situ-lithiated Nb2O5 diffusion barrier at the interface, it was possible to lower the LLZO / LCO charge transfer resistance to about 50 Ω cm2, a 3-fold reduction with respect to previously reported values. The low interfacial resistance combined with the high conductance through the LLZO thin-film electrolyte allows charge transfer at high charge–discharge rates up to 40 C (0.9 mA/cm2).[2]

References

[1] Sastre, Jordi, et al. "Lithium Garnet Li7La3Zr2O12 Electrolyte for All‐Solid‐State Batteries: Closing the Gap between Bulk and Thin Film Li‐Ion Conductivities." Advanced Materials Interfaces (2020): 2000425.
[2] Sastre, Jordi, et al. "Fast Charge Transfer across the Li7La3Zr2O12 Solid Electrolyte/LiCoO2 Cathode Interface Enabled by an Interphase-Engineered All-Thin-Film Architecture." ACS Applied Materials & Interfaces 12.32 (2020): 36196-36207.
Evaluation of Properties of DNA Methyltransferase M. Ape from Hyperthermophilic Archaea Aeropyrum Pernix
Authors: Hayashi Mao , Iida Yasuhiro 
Published: December 2020

DNA methylation is one of the epigenetic modifications that have significant functions in eukaryotic cells such as regulation of gene expression and imprinted gene. Also, it has significant functions in prokaryotes such as R-M system, regulation of cell cycle and mark to daughter strand in the DNA replication. DNA methyltransferase exists in eukaryotic, prokaryote and archaea. However, N5-cytosine DNA methyltransferase from hyper-thermophilic archaeon hasn’t reported. In our laboratory, we focus on methyltransferase M. Ape from hyper-thermophilic archaeon. This enzyme is estimated to have characteristics of thermostability. If it reveals to the characteristics of M. Ape that we will be able to apply to new technology. In this study, we investigated the recognition sequence and the position of the modified methyl group.
At first, we performed alignment analyses M. Ape and N5-cytosine methyltransferase from eukaryotic. As a result, we observed it has the common motif of N5-cytosine methyltransferase. And then, we determined the recognition sequence of M. Ape. In this experiment, 7 kinds of the substrate as Oligo DNA were used. We evaluated the recognition sequence from the activity of methyltransferase against these substrates. As a result, GCWGC sequence was the most reactive substrate against M. Ape. Further, as a result of bisulfite sequencing, it was clarified APE_0872 modified the methyl group to the second cytosine of GCWGC.
Furthermore, we tried the determination of the position of the methyl group to cytosine by M. Ape with use for HPLC. The column (InertSustain AQ-18) was used for the separation and the flow rate was 1.0 mL/min. We used 0.1 % formic acid in water(A) and 0.1 % formic acid in methanol (B), buffer B was increased with linear gradient 1.5 %/min from 0 % to 22.5 %. The peak from the sample was observed similarly retention time of 5mC of authentic samples. Thus, it was suggested that M. Ape modify N-5 cytosine.