bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Technique to Analyze the Electrolyte Wetting Rate through Li-Ion Battery Electrodes
Authors: Davoodabadi Ali , Li Jianlin , Wood David L. , Jin Congrui 
Published: February 2020

The electrolyte wetting step is one of the most critical processes in lithium-ion battery (LIB) manufacturing that typically requires a long period of time. Rapid and complete electrolyte wetting is extremely beneficial for reducing the wetting time, hence eliminating the bottleneck and saving substantial capital cost in battery production plant.
The wetting balance technique has been conventionally used to measure the electrolyte imbibition rate in electrodes, however, it suffers from several drawbacks and has limited accuracy. We presented a combined experimental and theoretical investigation of the dynamics of electrolyte imbibition through electrodes. We proposed a novel method to accurately measure the electrolyte imbibition rate. Excellent agreement between the experimental data and the developed analytical model is obtained, which demonstrates the robustness and accuracy of the proposed technique. The coefficient of penetrance (COP) and the solid permeability coefficient (SPC) are identified as important parameters, i.e., the electrolyte with higher COP value wets faster into an electrode, whereas for an electrolyte, the electrode with greater SPC is more amenable to impregnation. We utilized this technique to study the effect of different LIB parameters on electrolyte wetting rate. For example, as shown in Fig. 1 [1], the imbibition coefficient (D) that represents the electrolyte wetting rate decreases by increasing the electrolyte salt concentration. Electrolyte solvent, and calendering extent are among other factors that their effects on imbibition rate have been investigated. Such results can greatly help optimize electrolyte formulation and electrode design to achieve rapid and complete wetting, potentially leading to reduced battery production costs and improved product quality.
[1] A. Davoodabadi, J Li, Y Liang, DL Wood III, TJ Singler, C Jin; “Analysis of electrolyte imbibition through lithium-ion battery electrodes”, Journal of Power Sources, 424, 193-203 (2019)

Figure 1
Investigating a Novel Layer-By-Layer Coating Electrode Manufacturing Process for High Energy Batteries
Authors: Wu Qiang , Zheng J.P. 
Published: February 2020

Within the decades, there has been immense effort focused on reducing the cost and increasing energy density of energy storage devises. Optimizing cell engineering through tuning the electrode architecture is a straightforward approach to meet the cost and performance requirements of different application.
Layer-by-layer architectures have been proposed to provide precise control over the spatial arrangement of electrode materials, as well as tailoring various electrode components or formulations in each layer for specific purpose [1]. This facile multi-layer of the electrode structure can be created by layer-by-layer coating process, which can enable lower the cost and increase the energy density by manufacturing of thick battery electrodes.
Here we present a systematic study where the layer-by-layer coating process is investigated in order to identify the best possible combination of multi-layer low cost and high energy density electrodes. The silicon and graphite based materials are evaluated for the multi-layer anode. Both wet and dry methods are used to make multi-layer anode electrode including conductive layer, silicon-based anode layer and graphite anode layer. Free standing graphite anode sheet made by our advanced dry coating electrode technology [2] provide the facile way for the layer-by-layer coating process. In addition, the electrochemical performance of electrode with various binders such as CMC, PAA and Na alginate are also compared.
A Facile and Scalable Processing Method for 3-D Nanostructured Copper Current Collectors to Enable High Energy Li-Metal Batteries
Authors: Ma Yifan , Ma Xuetian , Chen Hailong 
Published: February 2020

Lithium metal is a promising anode for high-energy-density batteries owing to its high theoretical capacity and highly negative electrochemical potential. However, its commercial application is stalled by the undesired dendritic growth of lithium during cycling.[1]Among all kinds of promising approaches (e.g. electrolyte engineering, interfacial engineering, use of solid electrolyte and use of 3-D structured current collectors, etc. )
[2], 3-D structured current collectors represent some new promises as they can effectively increase Li nucleation sites and reduce local current. However, most of these successes are at lab-scale with coin cells and most of the methods are sophisticated and expensive, not scalable and compatible with the roll-to-roll manufacturing processes of current Li-ion battery industry.
Here we report a facile electrodeposition process for low- cost, scalable fabrication of copper current collectors with 3-D architected porous structures composed of interconnected Cu nanoparticles.[3]Compared to flat foil current collectors, the deposited 3-D nanostructured Cu current collector has much larger active surfaces area, thus effectively reduces the actual current density for the same apparent current and lowers the possibility of triggering dendritic growth. During Li plating process, Li can be accommodated in the porous structure and on the top surface of the 3-D nanostructured Cu current collector, which effectively suppresses Li dendrite formation and provides a very high practical Li storage areal capacity. The nanoporous electrodeposition coated Cu foil can be produced with very low cost and this foil can be seamlessly incorporated into current Li-ion battery production with no major modifications required. The electrodeposition method also provides great flexibility and tunability of the deposited structure, which suggests more Li may be accommodated and ultrahigh energy density batteries may be developed along this promising approach.

Harry, K.J., et al., Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes.Nat. Mater., 2014. 13(1): p. 69-73.

Lin, D., Y. Liu, and Y. Cui, Reviving the lithium metal anode for high-energy batteries.Nat. Nanotechnol, 2017. 12(3): p. 194-206.

Ma, X., Z. Liu, and H. Chen, Facile and scalable electrodeposition of copper current collectors for high-performance Li-metal batteries.Nano Energy, 2019. 59: p. 500-507.
(Invited) Towards Scalable Manufacturing of Solid State Batteries
Authors: Doeff Marca , Yi Eongyu , Shen Hao , Chen Guoying , Sofie Stephen 
Published: February 2020

The use of ceramic electrolytes like LLZO (variants of Li7La3Zr2O12) hold great promise for improving safety and increasing practical energy densities of batteries with lithium metal anodes. However, the thin film configurations that are currently employed in devices based on ceramic components are not readily scalable, limiting the applications for which these batteries can be used. Moreover, practical energy densities fall far short of the theoretical values because of the low areal capacities of the cathodes. We are currently exploring an alternate approach to the fabrication of solid state batteries based on a low-cost, eco-friendly, and continuous processing method known as freeze tape casting (FTC). In this method, an aqueous slurry of LLZO (or any other ceramic electrolyte of interest) is tape cast over a cold surface. If the conditions are selected correctly, columnar ice crystals form in such a way as to exclude particles. The ice is then removed by freeze-drying, resulting in a porous green body, which then can be sintered to strengthen the pore walls. By changing formulations, temperatures, and other experimental parameters, the thicknesses, porosities, and pore sizes of the scaffolds can be varied. The resultant porous scaffolds can then be infiltrated with active material and other components to make composite cathodes. The low tortuosity of the pores (approaching t=1) in a typical FTC scaffold is beneficial for the infiltration process and also shortens lithium diffusion pathways.
A goal is to make electrodes similar in thicknesses and loadings to what is used for cathodes in conventional lithium ion batteries (~100 mm, >75 vol.% porosity), to maximize energy density. Freestanding scaffolds this thin are somewhat fragile. Supporting the porous layer on a thin, dense electrolyte layer results in a more robust configuration. A lithium foil can then be attached to this bilayer to form the cell. A porous/dense/porous trilayer has additional manufacturing advantages. In this sort of configuration, lithium metal or another anode material is infiltrated into one of the porous layers, and a cathode material (and other components) into the other.
For this talk, we will discuss the challenges of fabricating solid state cells for large scale applications like electric vehicles, and show examples of FTC components and cells made in our labs.
Large Enhancement of Oxygen Surface Exchange Kinetics in Ruddlesden–Popper Thin Films By Thickness Controlled Strain
Authors: Zhu Shiyue , Yang Gene , Jung Wonsang , Lee Yueh-Lin , Huang Kevin , Lee Dongkyu 
Published: February 2020

The design of highly active catalysts for the oxygen reduction reaction (ORR) that leads to the majority of efficiency loss is a critical requisite in the needs of intermediate temperature solid oxide fuel cells (SOFCs). Introducing the lattice strain of an epitaxial film induced by lattice mismatch with a substrate enables a new way to enhance the ORR at elevated temperatures. However, very limited available electrolytes to induce strains in high temperature electrochemical applications, in which yttria-stabilized zirconia (YSZ) uniquely satisfies both the growth requirements (i.e. lattice mismatch) and the electro-chemical requirements (i.e. ionic conductor and electronic insulator) impose a constraint on applying the lattice strain. The limited choice of substrates imposes a constraint on the range of lattice strains, which suggests the need to develop a new strategy to modulate the epitaxial strain for designing catalytically active materials.
In this work, we explore the dramatically enhanced ORR kinetics in the Ruddlesden–Popper oxide, LaSrCoO4 (LSC214), which have been highlighted as alternative cathode materials for intermediate temperature SOFCs grown on (001) YSZ substrates using film thickness to control the epitaxial strain. Pulsed laser deposition (PLD) is employed to deposit LSC214 thin films with four different film thicknesses. Electrochemical impedance spectroscopy (EIS) results demonstrate that the oxygen surface exchange coefficient (k
q) values of ~ 15 nm LSC214 thin film with only ~1 % in-plane tensile strain can be dramatically enhanced by up to two orders of magnitude compared to fully relaxed thicker films (~70 and 140 nm). We find that this enhancement is strongly associated with a change of the surface chemistry revealed from Auger electron spectroscopy (AES), which can lead to a change of the electronic structure, the oxygen 2p band center relative to the Fermi energy level. In addition, we also show no discernible change in the k
q values at low oxygen partial pressures regardless of the film thickness. This result suggests that the rate-limiting step for the oxygen surface exchange in LSC214 thin films changes depending on the oxygen partial pressure. Our work illustrates that controlling thickness is a new strategy to design highly active oxide materials for applications of complex oxides in the solid-state electrochemistry.
Investigation of Metallic Dendrite Growth in Electrolytes
Authors: Lei Chong , Sparks Taylor D , Virkar Anil V. 
Published: February 2020

The formation of the metallic dendrite in the electrolyte under electrolytic mode can contribute to the failure of the battery, which may result in dramatic fires. Under electrolytic conditions often degradation occurs which manifests as electrode delamination and formation of cracks. In this work, both solid and liquid electrolytes were used to investigate the in-situ metallic dendrite growth.
Sodium sulfur batteries have been widely used for energy storage. Also, sodium ion batteries operating at room temperature are under development. One of the modes of failure of these devices is the formation of metallic sodium dendrites. In this work, a two-phase material Na-β”-alumina+3YSZ has been used to investigate the sodium dendrite growth under electrolytic conditions. The mixed Na+ ion and O2- ion electrolyte was fabricated by the vapor phase process. The sample was sintered and converted with an embedded hole, which was achieved by a wax coated copper wire during the initial uniaxial pressing stage. Subsequently, a small plastic tube with 1M NaNO3 solution was put on the surface of the obtained disc. Silver wires were put into the NaNO3 solution and the embedded hole, they were connected with an amperemeter, a resistor, and a voltage generator. The disc was put under the microscope, and a voltage of 3.5V was applied. In-situ formation of sodium dendrites was observed. The current response and the voltage between the sample were recorded, and EIS was measured every 20 min.
Furthermore, the silver nitrate solution was used to investigate the formation of sharp silver dendrites. Several drops of silver nitrate solution were placed onto the surface of the glass slide, and a cover glass was used for protection. Two silver wires were immerged inside of the solution. By applying the voltage, the silver dendrites shoot out from the tip of the silver wire and also grow along the silver wire. The current response and voltage between the sample were recorded. EIS was measured every 10 min to get the Nyquist plots.
(Invited) Development of High-Performance Lithium-Ion Batteries in the 21st Century
Authors: Li Yangxing 
Published: February 2020

Development of High-Performance Lithium-ion Batteries in the 21st Century

Yangxing Li, Ph.D., Chief Scientist
Watt Lab, Central Research Institute, Huawei Technologies Co.,Ltd.
li.yangxing@huawei.com

High-performance lithium batteries are desirable in the modern society, especially on enhanced safety, improved energy density, increased rate capability and high temperature performance. In order to achieve high energy density for battery, significant efforts have been taken to develop high-capacity electrode materials, high-cut-off voltage cathode, and increased loading density. Some specific technical approaches to achieve high-performance lithium-ion batteries will be discussed here.
The Effect of Oxygen Partial Pressure and Composition on the Oxygen Reduction Reaction Properties of Ba0.5Sr0.5Fe1-XCuxO3-δ as a Cathode for Solid Oxide Fuel Cells
Authors: Abubaker Orrsam Aadil , Singh Kalpana , Thangadurai Venkataraman 
Published: February 2020

Solid oxide fuel cells (SOFCs) face hurdles in market acceptability due to their high operating temperatures, which typically ranges from 750 oC – 1000 oC. Thus, current research is moving towards lowering the operating temperature to an intermediate temperature range from 500 oC - 700 oC by developing intermediate temperature (IT)-SOFCs. However, during IT operation, conventional cathodes show sluggish oxygen reduction reaction (ORR) kinetics. Till now, perovskite-type oxides have been at the forefront because of their mixed ionic electronic conductive (MIEC) nature. Additionally, Co-based perovskites have shown high catalytic activity for ORR in IT-SOFC cathodes. However, Co-leads to additional cost, high thermal expansion coefficient and toxicity.
In this study, ORR properties of the Co-free perovskite-type Ba0.5Sr0.5Fe1-x
Cu
x
O3-δ (x = 0.05 and 0.2) (BSFCu) cathodes were investigated by utilizing electrochemical impedance spectroscopy (EIS). BSFCu powders were synthesized through the sol-gel method with a final sintering temperature of 1050 °C. Powder X-ray diffraction was used test chemical compatibility between BSFCu and La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) powders up to 1100 °C in air. Symmetrical cells of the following configurations BSFCu-LSGM/LSGM/BSFCu-LSGM were prepared for electrochemical measurements using varying ratios of cathode to electrolyte. Using a well-controlled set up, the effect of pO2
on the area specific resistance (ASR) for ORR of symmetrical cells was studied. BSFCu0.05-LSGM/LSGM/BSFCu0.05-LSGM showed the lowest ASR of 0.03 Ω/cm2 under ambient air at 800 °C, when sintered at 1000 °C. These ASR values are competitive with typical values for Co-based cathodes as reported in the literature. Thermo-gravimetric analysis, under O2/Ar atmospheres showed reversible oxygen intake/release capability of BSFCu powders, making them potential candidates for applications in oxygen-storage technologies.
Deposition of Conformal Catalyst Coatings on Porous Electrodes Using a Layer-By-Layer Surface Sol-Gel Process
Authors: Kane Nicholas John , Liu Meilin 
Published: February 2020

The state-of-the-art cathode of solid oxide fuel cells suffers from accelerated degradation and slow reaction kinetics for the oxygen reduction reaction (ORR). Surface modification of the cathode has been widely investigated and shown to greatly improve catalytic activity and prevent the formation of insulating phases. However, there is a need to improve the quality of the surface modification coatings while reducing the cost. In this presentation, we report a novel surface modification technique, coined layer-by-layer surface sol-gel (LbL SSG), for deposition of BaO and Pr2O3 on a porous La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode, greatly increasing the catalytic activity for ORR and tolerance against contaminants. This low-cost, liquid phase deposition technique produces conformal coatings with precise thickness control by utilizing alternating self-limiting reactions between chemisorbed metal alkoxides and water on hydroxyl-rich surfaces. The availability of many different metal alkoxide precursors previously proved in traditional sol-gel processes, capability to deposit at room temperature, and lack of expensive vacuum equipment make this technique extremely promising over other conformal deposition techniques such as atomic layer deposition. LbL SSG is shown to produce much more conformal coatings throughout the entire porous cathode and further reduce degradation over similar coatings produced via solution infiltration. Electrochemical impedance spectroscopy analysis shows a great reduction in polarization resistance of symmetrical cells with electrodes modified by catalyst coatings. Utilizing the precise thickness control of the layer by layer process via deposition cycle count, the optimum thickness is determined to be about 8 nm (derived from 30 cycles). Thinner films are shown to be instable, breaking down and degrading over the first 30 hours, while thicker films increase the polarization resistance due to the lower ionic conductivity of the catalyst coatings. The process also demonstrates excellent scalability and versatility by coating larger cathodes (one inch in diameter) and depositing various oxides using different metal alkoxide precursors.
Figure 1. SEM images of bare and coated porous electrodes showing the conformal BaO film deposited via LbL SSG. The polarization resistance versus time for various deposition cycle counts showing greatly improved stability for coated cells.

Figure 1
(Invited) Developing Carbon Catalysts for Selective Electro-Reduction of Carbon Dioxide into Target Products
Authors: Wu Jingjie , Zhang Tianyu 
Published: February 2020

Electrocatalytic reduction of CO2 into value added chemicals or fuels is a promising technique towards a carbon-neutral chemical process. The electrochemical reduction of CO2 is a complicated process involving multiple protons coupled electron transfer, theoretically resulting in a variety of products (e.g. CO, HCOOH, CH4, C2H4 and C2H5OH). Therefore, the major challenge in CO2 reduction lies in the manipulation of the selectivity towards a specific product as demanded. However, the study on CO2 reduction has not substantially advanced primarily because of the lack of fundamental understanding of the reaction mechanism and the challenge of discovering efficient and robust catalysts for the various multi-electron transfer processes. Researchers have screened a wide range of metal-based materials for electrochemical reduction of CO2, and found only copper-based metals exhibit selectivity towards formation of hydrocarbons and oxygenates at fairly high efficiencies while most others favor production of carbon monoxide or formate.
Here we present the development of carbon materials as an alternative to Cu for efficient and high-rate electro-reduction of CO2 into hydrocarbons and oxygenates. We will discuss the key structural and electronic factors that govern the selectivity of carbon catalysts towards production of CO, CH4 and C2 products (e.g. C2H4 and C2H5OH). Three categories of carbon catalysts were developed based on the primary products of CO, CH4 and C2H4 in our group. The first carbon catalyst featuring the metal-nitrogen-carbon structure exclusively catalyzes CO2 electro-reduction into CO. The second catalyst called functionalized carbon nanostructure can selectively reduce CO2 into CH4 with Faradaic efficiency up to 90% while the third one namely doped carbon nanostructure (e.g. N-doped graphene quantum dots) can yield C≥2 products with a Faradaic efficiency up to 70%. Both carbon nanostructure can achieve partial current density at the scale of 100 mA cm-2 for target product at fairly low overpotentials. This study provides in-depth insights into developing high-performance carbon-based catalysts for electrochemical reduction of CO2.