bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Data-Driven Materials Design for Compounds with Improved Mg Intercalation Mobility
Authors: Liu Miao , Rong Ziqin , Zimmermann Nils , Haranczyk Maciej , Ceder Gerbrand , Persson Kristin A
Published: February 2020

The increasing demand of solid-state energy storage requires improved technologies, such as Mg-ion batteries, to address safety and cost concers as well as the energy density limitations of state-of-the-art Li-ion battery technology, however, the realization of Mg-ion batteries hinges on the discovery of host materials that possess sufficiently high voltage, large energy capacity, and, most importantly, adequate mobility of the Mg2+ to ensure the viable intercalation cycling. To date, there has only been a limited number of examples demonstrating the feasibility of rechargeable Mg-ion batteries, motivating the current investigation to search over more broad chemical spaces for attainable multivalent (Mg2+, Ca2+, Zn2+) intercalation cathode candidates. In this presentation, we show our detailed work, based on the robust automated high-throughput density functional calculations and the high-quality theoretical data from Materials Project, to systematically evaluate the electrochemical performance as well as the intercalating mobility of multivalent cation over several hundreds of host compounds. We also demonstrate our in-house theoretical approaches (e.g., diffusion path topology analysis) that have been designed and practiced to quantitatively estimate the multivalent cation mobility. Our study suggests that the matching between the intercalant site preference to the diffusion path topology of the host structure plays a decisive role to control mobility more than any other factor.[1] Our “in silico” design and evaluation have found several promising Mg-ion cathode materials that possess improved Mg mobility (migration activation energy lower than 600meV) [2,3], and some of them have been confirmed by experimental research teams recently [4]. The results demonstrate that the data-driven computational materials design is a realistic tool to the successful discover and optimize new materials for energy-dense multivalent batteries.

The work is entirely supported by the Department of Energy as part of the Joint Center for Energy Storage Research (JCESR).

[1] Z. Rong, R. Malik, P. Canepa, G. Gautam, M. Liu, A. Jain, K. Persson and G. Ceder, Materials Design Rules for Multi-Valent Ion Mobility in Intercalation Structures, Chem. Mat. 2015, 27, 6016.

[2] M. Liu, Z. Rong, R. Malik, P. Canepa, A. Jain, G. Ceder and K. Persson, Spinel compounds as multivalent battery cathodes: a systematic evaluation based on ab initiocalculations, Energy Environ. Sci. 2015, 8, 964.

[3] M. Liu, A. Jain, Z. Rong, X. Qu, P. Canepa, M. Ralik, G. Ceder and K. Persson, Evaluation of sulfur spinel compounds for multivalent battery cathode applications, Energy Environmental Science, Energy Environ. Sci. 2016, 9, 3201.

[4] X. Sun, P. Bonnick, V. Duffort, M. Liu, Z. Rong, K. Persson, G. Ceder and L.F. Nazar, A High Capacity Thiospinel Cathode for Mg Batteries, Energy Environmental Science, Energy Environ. Sci. 2016, 9, 2273.
Ionic Conductivity of Doped Lanthanum Gallate and Strontium Gallate Composites
Authors: Reis Shirley Leite , Muccillo Eliana Navarro Santos
Published: February 2020

Polycrystalline ceramic materials based on strontium- and magnesium-doped lanthanum gallate exhibit high ionic conductivity compared to the conventional yttria-stabilized zirconia, and find potential application as solid electrolyte for solid oxide fuel cells operating at intermediate temperatures (500-700°C). Sintering of this solid electrolyte is usually carried out at high temperatures being responsible for loss of Ga and consequent formation of impurity phases. In this work, the composition La0.9Sr0.1Ga0.8Mg0.2O3-
δ with small additions of strontium gallate was prepared by solid state reaction and the influence of the additive on electrical conductivity and phase composition of the solid electrolyte was investigated. The sintered density of composites is higher than 95% of the theoretical value and the average grain size amounts 2.40 µm after sintering at 1350°C. The contents of impurity phases decreased with increasing strontium gallate additions. The overall ionic conductivity is higher for composites than that of the base material.
(Invited) Solid Oxide Fuel Cell Development at Redox Power Systems, LLC
Authors: Bishop Sean R. , Wang Lei , Langdo Thomas , Blackburn Bryan M.
Published: February 2020

Redox is developing solid oxide fuel cell (SOFC) distributed power generation systems for commercial, light industrial, and residential markets. Benefits to long-term stability and reduced cost from a much lower operation temperature (500-650 oC) as compared to more conventional SOFC products (800 – 1,000 oC) are key advantages of the Redox technology. Furthermore, the Redox cell obtains stable, high power densities (>1 W/cm2) at these low temperatures, enabling reduced size, weight, and most importantly, the cost of reliable on-site generation of electricity. The modular nature of our system design lends itself to constructing systems with a broad range of power generation capacities and fuel options. In this presentation, we will highlight recent Redox SOFC achievements, with focus on materials, and how choices there impact overall system performance and operation considerations.
Mitigation of Chromium Poisoning Effects in SOFCs By Cathode Compositional Modifications and Interconnect Coatings
Authors: Gong Yiwen , Zhu Yuexing , Sun Zhihao , Basu Soumendra Nath , Pal Uday Bhanu , Gopalan Srikanth
Published: February 2020

Solid oxide fuel cells (SOFCs) address critical needs in the energy infrastructure due to their high efficiency, low emisssions and noiseless operation. The intermediate temperature SOFCs(IT-SOFCs) enable the use of metallic interconnect instead of traditional ceramic interconnect. However, chromium poisoning due to transport from metallic interconnect and BOP components is deleterious to cell performance.

To prevent the chromium poisoning, either a new cathode material with a high tolerance of chromium poisoning needs to be deployed, or a protective coating with a high electrical conductivity needs to applied to the interconnect.

In this study, electrolyte-supported baseline half-cell with 8mol% YSZ as the electrolyte and (La0.8Sr0.2)0.95MnO3-δ as the working and counter electrode was fabricated. Its electrochemical characteristics were tested in dry air and 50 mA/cm2 cathodic current in the present of bare chromia-forming interconnect, and an interconnect with a protective coating. Further, to investigate the effect of alternate electrode compositions, new electrodes, e.g. Cr- doped LSM, were employed as the working electrode instead of LSM in the baseline cell, and tested under same conditions.
Long Term Testing of Solid Oxide Electrolysis Cells under Co-Electrolysis Conditions
Authors: Rao Megha , Sun Xiufu , Hagen Anke
Published: February 2020

The increasing use of renewables for energy production brings about challenges, for instance, regarding the storage of electricity. Highly efficient solid oxide electrolysis cells (SOECs) can become an attractive solution for converting excess electricity into hydrocarbons (Power-to-Gas). The use of electricity to produce synthetic methane, especially, is considered as a part of the energy transition due to available infrastructure for storage and distribution.

In this contribution, state-of-the-art (SoA) SOECs consisting of a Nickel-Yttria Stabilized Zirconia (Ni-YSZ) fuel electrode, YSZ electrolyte and a mixed ionic electronic conductor (MIEC) Lanthanum Strontium Cobalt Ferrite-Gadolinium doped Ceria (LSCF-GDC) oxygen electrode were tested under co-electrolysis (H2O+CO2) conditions where the ultimate goal is to produce methane. The SOEC durability tests are traditionally carried out in galvanostatic mode due to the straightforward test control and data interpretation. In this mode, the cell voltages change due to degradation and reach values that are either above or below the thermoneutral voltage which lead to either endothermic or exothermic processes lowering the cell efficiency. However, from a SOEC system point of view, operating the SOEC at thermoneutral voltage (i.e. potentiostatic) is attractive yielding a more efficient system with a comparatively easier heat management. The aim in this study was to compare the SOEC durability under co-electrolysis conditions between galvanostatic and potentiostatic mode. Specifically, the cell was operated at 0.75 A/cm2 (galvanostatic) and at 1.2 V (potentiostatic) at 750 oC for 1000 hours and 500 hours respectively. A detailed electrochemical and microstructure analysis for the two testing regimes will be presented. The degradation mechanisms associated with individual electrode performance will be comprehensively discussed.
Dynamic and Impure Perovskite Structured Metal Oxide Surfaces
Authors: Hansen Karin Vels , Norrman Kion , Traulsen Marie Lund , Mogensen Mogens Bjerg
Published: February 2020

During recent years a lot of results on segregation of metal oxide components to the surfaces of perovskite electrodes for solid oxide cells (SOC) have been published. The electrodes are typically of the families (La1-xSrx)sMO3, M = Mn, Fe, Co, Ni with 0 < x < 1, and s is the so-called A/B ratio, usually 0.9 < s < 1.1. M may in principle be a mixture of all four metals, and the mentioned transition metals are only examples. Especially SrO segregations have been reported, but other of the components of the perovskite may also segregate to the surface as well as impurities in the raw materials. Finally, impurities from the reactant gases may adsorb to the surface of such electrodes (1 - 5).

However, it has been suggested that e.g. the SrO segregation is due to the vacuum based ex situ analytical tools such as low energy ion scattering (LEIS), x-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS). In general, the literature results are quite scattered, so the issue is still open for discussion.

The aim of this paper is to settle this discussion. First a brief summary of some main literature results are given, and next some results of our own on studies on popular commercial perovskite materials are presented and discussed. The methods used are Raman spectroscopy and XRD, which are not vacuum techniques, and ToF-SIMS and XPS, which are vacuum techniques.

The conclusion is that usually a perovskite surface will be covered with segregated material of as well components like SrO as impurities in the perovskite starting material. Furthermore, the available evidences point to the perovskite surfaces being very dynamic with relatively fast changes that are visible within periods of few hours with developments continuing for hundreds of hours.

Acknowledgement

We acknowledge financial support from Energinet.dk through the ForskEL programme Solid Oxide Fuel Cells for the Renewable Energy Transition contract no. 2014-1-12231, and by The Energy Technology Development and Demonstration Program (EUDP) at the Danish Energy Agency via project “Maturing SOEC”, contract no. 64015-0523.

References

K. Norrman, K.V. Hansen, T. Jacobsen, RSC Adv., 5, 87679 (2015).

F.S. Baumann, J. Fleig, M. Konuma, U. Starke, H.-U. Habermeier, J. Maier, J. Electrochem. Soc.,
152, A2074 (2005).

J. Druce, H. Tellez, M. Burriel et al., Energy Environ. Sci., 7, 3593 (2014)

Z. Cai, Y. Kuru, J. W. Han, Yan Chen, Bilge Yildiz, J. Am.
Chem. Soc.,
133, 17696 (2011).

K.V. Hansen, K. Norrman, T. Jacobsen, Y. Wu, M.B. Mogensen, J. Electrochem. Soc., 162, F1165 (2015).
Innovative Approach on Nano-Metal Particles of Electrodes for Solid Oxide Cells
Authors: Myung Jae-ha , Neagu Dragos , Irvine John T. S.
Published: February 2020

Solid oxide cells (SOCs) are electrochemical systems capable of operating reversibly and therefore may serve as versatile energy converters. Electrolysis mode, electricity can be converted to fuels or other valuable chemicals, on the other hand, fuel cell mode converts efficiently fuel to electricity on demand. Due to their severe operating conditions, the ideal fuel electrode materials has not been found yet to accomplish of its requirements such as electronic and ionic conductivity, and catalytic activity with strong stability in redox condition, while several high performance air electrode materials -have been identified. For a long time, Ni-YSZ cermet has been regarded as the embodiment of this functional trinity. However, even though degradation associated with reversible operation can be mitigated, the cermet electrodes still suffered from agglomeration during redox condition. Recent electrode designs have been developed to microstructures consisting of a porous mixed ionic electronic conductor backbone decorated with metallic nanoparticles (typically Ni) by impregnation method. However, these are still hindered by the lack of cost and time-effective methods to produce both robustness and high-performance from their nanostructured electrodes. Here, a simpler alternative, will be introduced, exsolution whereby the catalytically active metal is substituted in the crystal lattice of the backbone in oxidizing conditions and exsolved on the surface as designed metal particles under reduction condition. Here we demonstrated a simple and highly effective in situ method for producing nanostructured electrodes capable of delivering high performances in both fuel cell and electrolysis mode. Both the nanostructures and corresponding electrochemical activity show no degradation over 150 hours of testing.
Microstructural Characterization of Solid Oxide Fuel Cell Anodes Operating on Hydrocarbon Fuels
Authors: Robinson Ian , Abdul Jabbar Mohammed Hussain , Huang Yi-Lin , Wachsman Eric D.
Published: February 2020

Solid Oxide Fuel Cells (SOFCs) are an interesting energy conversion device due to their fuel flexibility feature and high fuel conversion efficiency. Reducing the performance losses associated with fuel electrode is critical, especially when SOFCs are operated on hydrocarbon fuels. The fuel electrode in an SOFC has typically been a cermet of Ni-YSZ whose degradation mechanisms have been thoroughly studied. Recently, the focus of SOFC research has shifted towards a lower operating temperature range (400-650 oC) to achieve reliability and cost competitiveness among other energy conversion technologies. The use of a Ni-GDC cermet anode allows SOFCs to operate on hydrocarbon fuels at lower temperatures compared to (>800 oC) for Ni-YSZ. However, Ni-based anodes have several challenges that have to be resolved for efficient operation of SOFCs. Evaluating the microstructural changes such as coarsening and carbon formation when exposed to hydrocarbon fuels is essential to understand the underlying degradation mechanism and to overcome the issues. This study focuses on a) evaluating the chemical compatibility of Ni-GDC cermet anode when exposed to harsh operating conditions and b) to propose a possible degradation mechanism at low temperature ranges by carefully examining the microstructural changes on samples that are aged in hydrocarbon containing fuels.
In-Depth Investigation of Process-Structure-Property Relationship in the Cathode Materials for Li Ion Batteries
Authors: Liu Qi , Xie Jian , Ren Yang , Lu Wenquan
Published: February 2020

For li ion batteries, the cathode materials are typically metal oxides or phosphates. Among the commonly-used cathode materials, V2O5 have been considered to be very promising cathode materials. However, the long-standing issues of low intrinsic electronic conductivity, slow lithium-ion diffusion and irreversible phase transitions on deep discharge prevent the high specific capacity/energy vanadium pentoxide from being used as the cathode material in practical battery applications. In this talk, our presentation will be centered on the study of V2O5 as the cathode materials for Li-ion batteries. Here we develop a method to incorporate graphene sheets into vanadium pentoxide nanoribbons via the sol–gel process. The resulting graphene-modified nanostructured vanadium pentoxide hybrids contain only 2 wt. % graphene, yet exhibits extraordinary electrochemical performance. Finally, the in-depth investigation of process-structure-property relationship in these hybrids-based Li-ion batteries has been studied using advanced in situ synchrotron techniques and existing tools.
Primary and Sub-Primary Particle Level Lithium Ion Battery Diagnostics Using Chemical-Sensitive STEM Tomography, Aberration-Corrected Imaging and Eels
Authors: Lin Ruoqian , Hu Enyuan , Yu Xiqian , Yang Xiao-Qing , Xin Huolin L.
Published: February 2020

The results of using newly developed chemical-sensitive scanning transmission electron microscopic (STEM) tomography, aberration-corrected imaging, and STEM-EELS to study structural changes of electrode materials for Li-ion battery will be reported. Some initial results regarding the structural irreversibility and chemical segregation of layer-layer compounds relating to their composition will be discussed as an example. Our results show that upon charge/discharge cycles, it is possible to use STEM tomography to three-dimensionally resolve the internal pore structure and its development with sub-nanometer resolution. This structural degradation is correlated with chemical segregation of the electrode materials at two drastically different length scale—single-digit nanometer and sub-micron length scales. Using our experimental results as a direct input for our high-throughput ab initio calculations, we are able to show that the solubility of transition metals in a specific solid phase can be used as an important parameter in predicting the structural reversibility of transition metal cathode materials.

Acknowledgements

This work was supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (BMR and VTO Battery500 projects) under Contract Number DE-AC02-98CH10886 This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704
Using Electrochemical Impedance Spectroscopy and Equivalent Circuit Modeling to Analyze Capacity Fade in Lithium-Ion Batteries Due to Pulse Charging
Authors: Rajagopalan Kannan Dhevathi Rajan , Butts Latarence J. , Weatherspoon Mark H. , Moss Pedro L.
Published: February 2020

Battery life is a critical and challenging issue for battery development and applications. The capacity of lithium-ion batteries reduces during continuous discharge-charge cycling. This capacity fade or loss occurs due to different mechanisms which are associated with side reactions that occur in these batteries [1]. The objective of this work is to use electrochemical impedance spectroscopy (EIS) to study the effects of pulse charging on the capacity and cycling characteristics of lithium-ion cells and compare it with conventional charging method at constant current-constant voltage (CCCV). Implementing conventional charging and pulse charging at an average of 0.5C and 1C on 18650 Lithium Iron Phosphate batteries separately provides varied results in capacity after few cycles. Equivalent circuit models are extracted from the measured EIS data for both of the charging methods to provide detailed results on capacity and battery performance.

 

Reference:

[1] P. Arora, R. E. White, and M. Doyle, “Capacity Fade Mechanisms and Side Reactions in Lithium‐Ion Batteries,” J. Electrochem. Soc. , vol. 145, no. 10, pp. 3647–3667, Oct. 1998.

Figure 1
In Situ Observation of Lithium Dendrite Growth and SEI By Optical Microscopy and Raman Spectroscopy
Authors: Kuo Li-Ming , Lo Wen-Tse , Hwang Bing-Joe , Cheng Ju-Hsiang , Su Wei-Nien , Assegie Addisu Alemayehu
Published: February 2020

Li metal negative electrode is expected for the next-generation Li battery electrode material due to its extremely high theoretical specific capacity (3,860 mAhg-1), low density (0.534 g cm-3) and the lowest negative electrochemical potential (-3.040 vs standard hydrogen electrode). However, the critical challenges of Li metal anodes (poor cycle life and safety) remain unsolved. This is attributed to electrolyte decomposition and the Li dendrite growth during electrochemical cycling.

In this study, we developed a transparent two-electrode cell to carry out an in situ observation of the Li dendrite growth on Cu surface. Galvanostatic plating and stripping cycle(s) are applied at same current density on each cell. Meanwhile, the Raman spectroscopy is employed to take a mapping image along with the grown lithium surface. The morphology evolution of the Li dendrite growth and nucleation mechanism is observed in different electrolytes and additives. The behavior of lithium dendrite and SEI were analyzed comparatively with 1M LiPF6 EC/ DEC (v: v=1:1), 1M LiTFSI, DME/DOL (v : v=1:1), and 1M LiClO4, PC electrolyte at the same current density. We have clearly observed that after a few cycles of platting and stripping lithium dendrite grew dramatically on Cu surface with carbonate electrolyte and the Cu surface still remained some lithium dendrite due to the dead lithium formation, which causes low Coulombic efficiency. In addition, Raman spectroscopy is used to probe SEI composition. The correlation of lithium growth and its surface composition are established in this work, which can help to further understand the mechanism of lithium growth.
Understanding the Electrode/Electrolyte Interface Formation on Positive Electrodes of Li-Ion Batteries
Authors: Karayaylali Pinar , Giordano Livia , Yu Yang , Chang Hao-Hsun , Maglia Filippo , Lux Simon , Lund Isaac , Paschos Odysseas , Lamp Peter , Shao-Horn Yang
Published: February 2020

Understanding electrode/electrolyte interface (EEI) is crucial for the development of high-energy batteries for electric vehicle applications. The EEI layer formation of negative electrode (also referred as Solid Electrolyte Interphase) is comprehensively studied [1,2], whereas the electrolyte decomposition and formation of the EEI layer at the positive electrodes are still unknown [3,4]. Especially, at high potentials, the role of oxygen in the transition metal oxide becomes critical, leading to the evolution of oxygen from the oxide lattice or the formation of highly reactive species like surface peroxide and superoxide, which can modify the nature of the EEI layer.

Here, we show how EEI layer depends on different positive electrodes (LiCoO2 and NMC electrodes with different Ni content) and different electrolyte additives (diphenyl carbonate and adiponitrile) by using X-ray Photoelectron Spectroscopy (XPS). We also highlight the importance of using carbon-free, binder-free electrodes to unambiguously pinpoint the reactivity of the electrolyte at the positive electrode [5]. The analysis of the XPS results points to a strong dependency of the surface reactivity on different electrode and electrolyte composition.

[1] E. Peled, J. Electrochem. Soc. 126, 2047 (1979).

[2] D. Aurbach et al., J. Power Sources 81-82, 95 (1999).

[3] K. Xu et al., Chem. Rev., 114, 11503 (2014).

[4] M. Gauthier, T. Carney, A. Grimaud et al., J. Phys. Chem. Lett. 6, 4653 (2015).

[5] M. Gauthier et al., in preparation.
Effects of Additives in Dual-Salt/Carbonate Electrolytes on Performances of Lithium Metal Batteries
Authors: Li Xing , Ren Xiaodi , Engelhard Mark H , Li Qiuyan , Zhao Wengao , Zheng Jianming , Adams Brian , Zhang Jason , Xu Wu
Published: February 2020

The lithium (Li) metal battery (LMB) is a promising high-energy-density energy storage system. However, the uncontrollable dendrite formation and low Coulombic efficiency (CE) associated with the Li metal anode have largely hindered the practical application of LMBs [1]. During recent years, extensive efforts have been made to address the main problems of Li metal anode and to improve the electrochemical performance of the related LMBs, and plenty of promising results have been achieved. Among the reported approaches, the reformulation of electrolytes with different Li salts and additives has been regarded as an easy and cost-effective method. The conventional LiPF6/carbonate electrolytes have been found to be detrimental to Li metal anode especially at high charge current densities, which is mainly due to the serious corrosion of Li metal anode, the consumption of electrolyte, the continuous formation of solid electrolyte interphase, and the increase of cell impedance. The highly concentrated electrolytes of LiTFSI or LiFSI in ethers have been reported to be effective to suppress Li dendrites growth and to improve the Li CE [2]. However, the ether-based electrolytes normally are not electrochemically stable at the voltages around or above 4 V. In our previous works, we have systematically investigated the dual-salt electrolytes of LiTFSI-LiBOB in carbonate solvent mixture and their effects on the performances of Li||LiFePO4
[3], Li||LiNi0.80Co0.15Al0.05O2
[4]
battery systems. It has been found that the dual-salt electrolytes are favorable to protect Li metal anode and to improve the rate capability of the LMBs. Especially, our recent work discovered that further significant improvements in fast charging capability and long-term cycling stability of the Li||LiNi0.4Mn0.4Co0.2O2 batteries can be achieved by adding an optimal additive amount of LiPF6 to the LiTFSI-LiBOB/carbonate electrolyte [5]. Nevertheless, this electrolyte still leads to relatively low Li CE, which is about 90.6%.

In order to further improve the Li CE of the dual-salt/carbonate electrolyte, we systematically investigated different additives such as VC, FEC, VEC, etc. By using certain additives the Li CE in the electrolytes of LiTFSI-LiBOB dual-salt in carbonate solvents can be improved from 90.6% to 98.1%. Moreover, the electrochemical performances of the LMBs with a 4-V Li-ion cathode using the newly developed dual-salt electrolytes were studied, and enhanced battery performances have been obtained. The promising results will be reported at the meeting.
Carbon-Coated Silicon Powders Prepared from Recycled Silicon Ingot Slicing Slurries and Biomass for Negative Electrode Materials of Li-Ion Batteries
Authors: Chou Che-Yu , Kuo Jing-Rong , Yen Shi-Chern
Published: February 2020

Silicon has the potential to replace the graphite as the anode material for LIB due to its high specific capacity and proper working voltage. However, the dramatic volume expansion during the Li-ion insertion and extraction has caused the poor cyclic stability. To improve the cyclic stability of Si anode, we embedded Si into a carbon matrix to form a Si-C composites. In this study, the silicon powders of micrometer size recovered from the silicon ingot slicing slurries and lignin, which is by-product of pulp industry, are employed to fabricate negative electrodes for lithium ion battery. The biomass would well mix with Si particles by magnetic stirring and ultrasonication, and then undergo a pyrolysis process to form Si-C composites. Depends on different carbonaceous precursors, the composites have different structures. The lignin-based Si particles are coated with a carbon layer, and the layer can not only suppress the volume change but also increase the electronic conductivity. The composite electrode exhibits outstanding cycle performance for capacity retention up to 60% after 51 cycles at 300 mA/g. On the other hand, the pyrolyzed lignocellulose formed an interconnected structure with Si particles, which provide extra space to accommodate Si volume variation. It showed excellent electrochemical performance with an initial charge capacity up to 1937 mAh/g and retaining 1275 mAh/g after 100 cycles at 300 mA/g. The utilization of renewable sources and industrial wastes for energy storage materials is well demonstrated in this study.
Electrochemical Studies of Solid Electrolyte and Cathode Composite for All Solid Lithium Secondary Battery
Authors: Yang Seung-Hoon , Kim Min-Young , Kim Da-Hye , Jung Ha-Young , Ban Hee-Jung , Ryu Hye-Min , Kim Ho-Sung
Published: February 2020

Recently, lithium ion batteries with high working voltage, high energy density and good cycle ability have been widely adopted as the most promising portable energy source in electronic devices. However, lithium secondary batteries have some safety problem due to using the liquid electrolytes. Solid electrolytes are one of the very important keys to realize all-solid-state secondary batteries with high safety and high energy density. The garnet structure solid electrolyte is great candidate solid electrolyte in all solid lithium ion battery. It is better than others in terms of electrochemical stability and high ionic conductivity. In this studies, garnet LLZO was doped with a different elements via. coprecipitation method in order to increase the ionic conductivity and structure stability. Bare LLZO powder with tetragonal structure was changed into cubic structure when the chemical elements were doped. Especially, the best doped LLZO showed an excellent crystallization with a high intensity peak, indicating the highest ionic conductivity of 7.11 x 10-4 S/cm due to the excellent sinterability.
Optimization of Crystal Structures for Cathode Materials of Li-Ion Battery Using Genetic Algorithm
Authors: Otake Masanari , Nakayama Masanobu
Published: February 2020

New cathode materials of Li-ion battery which realize large-reversible capacity are demanded urgently. Computational method is promising approach of material search and analysis. However, calculation of nonstoichiometric composition is technically difficult due to large degree of configuration freedom. To optimize structure with reasonable time, genetic algorithm (GA) is used in this study. To evaluate GA-derived structure, we used BV-FF calculations [1].

As an example, the variation of total energy of Li16Co16O32 for GA driven structures as a function of generation is shown in Fig.1. The structure framework is cation-disordered rocksalt-type structure and there are 32 cation site and degree of freedom of cation arrangement is 6×108. The red line indicates the lowest energy of GA generated structures among present and previous generations. Fig.2 shows the most stable structure obtained by GA. Green and blue colored octahedra correspond to LiO6 and CoO6, respectively. We confirmed the cation arrangement of most stable structure is layered rocksalt-type structure.

Reference [1] S.Adams et al, physica status solidi (a), 208(8), 1746-1753 (2011)

Figure 1
Simulation of Lithium-Ion Battery with Effect of Volume Expansion of Active Materials
Authors: Inoue Gen , Ikeshita Kazuki , Iwabu Minami , Sagae Yukari , Kawase Motoaki
Published: February 2020

In order to improve the performance of Lithium ion secondary batteries (LiBs) for electric vehicles and hybrid electric vehicles, it is very important to understanding the internal transport phenomena under high rate condition to increase power density. In our previous studies, we focused on the actual porous electrode structure, and the Li ion and electron conductivity was evaluated by the effective conductive path with the actual reconstruction electrode structure [1]. In addition, the charge-discharge performance was simulated with the model of reaction and mass transfer in heterogeneous porous electrode structure [2]. This model was developed with the multi-block method which is the method of coarse graining to keep the information of heterogeneous structure [3]. Furthermore, in order to design high capacity anodes based on volumetrically expanding active materials for lithium-ion batteries, we investigated the effects of the expansion ratio of active materials on the charge capacity by carrying out numerical simulations based on the porous electrode theory [4]. In this simulation, as assumptions, Li concentration and potential distribution in active material (AM) and electrolyte (EL) were calculated with Butler-Volmer equation as the boundary condition of the interface between AM and EL. it was assumed that temperature is constant, the formation of SEI is ignored, binder phase inhibit ionic transfer. From these calculation results, the effect of heterogeneous porous structure, which consist of active material, conductive material and binder, on the cell performance could be evaluated. Especially, we focused on the dynamic effective parameter which means the ratio of the effective ionic conductivity in porous electrode between the local time and the initial condition. In the case of expansion ratios of 0.5, which means the 50 % enlargement of active material at the SOC=100%, this value becomes approximately 0.24. Thus, the effective ionic conductivity decrease about 0.2 times than that at initial condition. However, in order to examine then in detail, there are some subjects. In this study, the effect of various expansion ratio and the aggregate structure of active materials was examined. And also, the validity of this simulation was evaluated with some experimental charge-discharge curve and direct observation of volume expansion. Figure 2 shows the cross section view of cell under charge condition and the change of electrode layer thickness. In our presentation, we will discuss the effect of the micro-scale structure on cell performance with volume expansion and the validity of this simulation.

Figure 1
Lithium Dendrite Suppression By Polyethylene Oxide Film Coating on Copper Electrode Enable Lithium Metal Anode
Authors: Assegie Addisu Alemayehu , Hwang Bing-Joe , Cheng Ju-Hsiang , Su Wei-Nien , Kuo Li-Ming
Published: February 2020

Efforts to realize lithium metal as anode limited by dendrite formation and low Coulombic efficiency. These challenges stem from extensive reaction of lithium with electrolyte, deposition of more dead lithium and formation of unstable solid electrolyte interface. Herein, we revealed a homogeneous lithium deposition and dendrite suppression via regulating lithium flux with polyethylene oxide (PEO) film coated copper electrode in 1M LiTFSI, DME/DOL (v/v 1/1) and 2 wt% LiNO3 electrolyte. PEO coating reinforces a thin and robust SEI layer film formation by hosting lithium and regulating the inevitable reaction of lithium with electrolyte. The modified electrode showed a stable and an extremely excellent Coulombic efficiency over 200 cycles with low voltage hysteresis (~30 mV) at rate of 1 C. In comparison the modified electrode tested with 1M LiPF6, EC/DEC (v/v 1/1) electrolyte and showed a rapid capacity fading due to PEO film damage with fluoride ion interaction. This enhanced cycle life and capacity retention results from the synergy of PEO coating, high electrode-electrolyte interface compatibility, stable polar oligomer formation from reduction of 1, 3-dioxolane and generation of SEI stabilizing nitrite and nitride upon lithium nitrate reduction in an ether electrolyte.
eQUMEC Software: Multiscale and Multiphysics Simulation/Designing of Li-Ion Batteries
Authors: Hosseinzadeh Hamed
Published: February 2020

eQUMEC software has been developed to design Li-ion batteries and other electrochemical systems like Li-air batteries and hybrid supercapacitors. This software has a 3D user interface to design the shape of electrochemical cell and related internal components. Microstructure of active materials could be defined by user such as powders size, shape and density. Conductive and adhesive materials could be also added to active materials. Defining and adding any kinds of electrolytes would be very simple in this software. eQUMEC has a toolbox for applying different charge and discharge conditions (constant voltage or constant current). eQUMEC has also other modules for calculating temperature and stress evolution during charging and discharging. This software has several more options like battery management systems (BMS) and thermal management systems (TMS). At last, voltage vs capacity, current/voltage vs time, Li ions concentration evolution in Li-ion cell and several other outputs would be extracted via a successful simulation. eQUMEC has several computational algorithms. The main computational algorithm is a coupled multiscale/multiphysics Fickian approach for ionic diffusion in active materials, Poisson Equation solver for potential in electrolyte, related conservative equation solver for calculating temperature and other equations solver to capture phenomena at interface of active materials and electrolyte. This software could be used by researchers and designers at research institutes, universities and companies to simulate new Li-ion batteries performance.

Figure caption: eQUMEC software interface which is showing cathode powders, final cell shape and calculated profile of Li ions concentration during charging.

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A Survey on High Rate Performance of LiNi0.5Mn1.5O4 As Cathode of Li-Ion Battery
Authors: Hosseinzadeh Hamed
Published: February 2020

In this research, high rate performance of LiNi0.5Mn1.5O4 cathode has been explained in details by a model, numerical simulation technique and experimental verification. The proposed model which was verified by experimental data and simulation could estimate the capacity dependency of LiNi0.5Mn1.5O4 to diffusion coefficient of lithium ions in active materials and c-rate of discharging. Results showed that LiNi0.5Mn1.5O4 has capacity higher than 80 mAhg-1 even for c-rate up to 10C discharging and facilitating the movement of lithium ions in active material and reducing thickness of electrolyte has reasonable impact on achievable final capacity of LiNi0.5Mn1.5O4. In addition, higher rate performance of mentioned active material would be enhanced by an increase in Li ion diffusion coefficient from 10-11 cm2.s-1 to 5×10-10 cm2.s-1 which was explained and verified by experiment. Achieved capacity at 200C would be less than 40 mAh.g-1 in cathode materials with Li ion diffusion coefficient 10-11 cm2.s-1. Whereas, cathode materials with Li ion diffusion coefficient 5×10-10 cm2.s-1 showed achieved capacity higher than 100 mAh.g-1 at 200C.

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ALD Al2O3 Coated TiO2 Nanotube Layers As Anodes for Lithium Ion Batteries
Authors: Sopha Hanna , Salian Girish , Zazpe Raul , Prikryl Jan , Hromadko Ludek , Djenizian Thierry , Macak Jan M.
Published: February 2020

Alumina coatings produced by Atomic layer deposition (ALD) on electrode materials have been explored extensively. Alumina coatings generally, have been used as a protective layer for the suppression of the solid electrolyte interphase (SEI) in various electrode materials.1 But its influence on increasing the electronic conductivity of the electrode material has not been explored. TiO2 nanotubes have been recently explored due to its low volume expansion, good capacity retention even at faster kinetics.2 The utilization of anodic TiO2 nanotube layers with uniform Al2O3 coatings of different thicknesses (prepared by atomic layer deposition, ALD) as new electrode material for lithium-ion batteries (LIBs) is reported. Electrodes with very thin Al2O3 coatings (~1 nm) show a superior electrochemical performance for the use in lithium ion batteries compared to uncoated TiO2 nanotube layers. A more than two times higher capacity is received on these coated TiO2 nanotube layers (~75 µAh/cm2 vs 200 µAh/cm2 at 1 C) as well as a higher rate capability and coulombic efficiency. Reasons for this can be attributed to a better diffusion of Li+ ions within the coated nanotube layers. However, thicker ALD Al2O3 coatings result in a passivation of the electrode surface and, therefore, in a capacity decrease. Fig. 1(a) shows the influence of alumina coating with different thickness on the capacity of the TiO2 nanotube layer. Fig.1(b) shows the long term cycling of the 1 nm alumina coated and the uncoated TiO2nanotube layers at 1C. In this work, factors influencing the increase in capacity due to the alumina coating will be discussed using results from different electrochemical characterization methods.

Fig. 1 (a) Galvanostatic cycling of the uncoated and the coated TiO2 nanotube layers at 1C (b) Long term galvanostatic cycling of the 1 nm thick alumina coated and uncoated TiO2nanotube layers at 1 C for 100 cycles.

References

1) Jung, Y. S.; Cavanagh, A. S.; Riley, L. A.; Kang, S.-H.; Dillon, A. C.; Groner, M. D.; George, S. M.; Lee, S.-H. Ultrathin Direct Atomic Layer Deposition on Composite Electrodes for Highly Durable and Safe Li-Ion Batteries. Adv.Mater. 2010, 22, 2172-2176.

2) Ortiz, G. F.; Hanzu, I.; Djenizian, T.; Lavela, P.; Tirado, J. L.; Knauth, P.; Alternative Li-Ion Battery ElectrodeBased on Self-Organized Titania Nanotubes. Chem. Mater. 2009, 21, 63-67.

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Analysis of Plating in Lithium-Ion Batteries with Anode Control
Authors: Juarez Robles Daniel , Minter Robert D. , Barsukov Yevgen , Mukherjee Partha P.
Published: February 2020

Lithium-ion batteries (LIBs) are the energy storage system of choice for high energy and power applications, such as electric vehicles. However, LIBs still face multiple challenges, especially during operation under extreme, such as low-temperature and fast charge. Under such conditions, lithium plating may happen, which can deplete the cell capacity, diminish cycle life and may lead to safety incidents. For example, if dendrites are formed, instead of a film-like lithium metal deposition, short circuit and thermal excursion may ensue. Graphite anodes are susceptible to lithium plating due to the proximity of their potential to the reversible potential of lithium. In a typical Li-ion cell, if the graphite anode potential is driven below 0.0 V vs. Li/Li+ during cycling, deposition of lithium may occur. In the present study, an anode control based charging scenario is proposed. Fast charging is conducted by imposing a constant current – constant voltage (CCCV) protocol in the negative electrode with an arbitrary lower cutoff potential (> 0.0 V vs Li/Li+). During the anode controlled charging, both the cathode potential and the full cell voltage are also monitored. Electrochemical analysis based on the anode control strategy and the effect on lithium plating and cell performance will be presented.
Origin of the Self-Limited Energy Density of Oxide Cathode Materials for Li-Ion Batteries
Authors: Wei Su-Huai , Zhang Peng
Published: February 2020

The increasing demand of modern society for clean energy has made it critical to develop novel battery materials with high energy density and cycling stability. Cathode materials of Li-ion batteries have been extensively studied in the past, and recently it has been proposed that by utilizing the anionic redox reaction one may be able to increase the total capacity of cathode materials. But the mechanism behind this proposal is not well understood because the traditional point of view is that the redox reaction is mainly carried out by the transition metal (TM) ions and experimentally achieved energy capacity is much lower than what is predicted by theory assuming all the Li ions can be extracted from the cathodes. In this work, we carefully study the general charge-compensation redox process of cathode materials upon delithiation, based on the molecular-orbital analysis and first-principles calculations. We reveal that the charge compensation in a cathode during the delithiation-lithiation process is mainly achieved by the oxygen redox reaction, and only partially by the TM redox reaction, due to a negative-feedback effect and the associated charge transfer from the O 2p to TM d orbitals. More importantly, our band structure and total energy calculations indicate that the energy density in a cathode is self-limited by the structural stability of its host upon delithiation, which depends on the energy level of the highest occupied states (HOS) of the host. When a critical amount of Li ion and electrons are removed from the host, the HOS becomes low enough to promote the formation of oxygen vacancy and thus destroy the host structure. As a result, suitable TM elements have to been used in the cathode materials to adjust the HOS level to keep a balance between energy density and stability, because the HOS is mainly determined by the TM for a given anionic framework. This new physical understanding and insights provided in this work on the redox process in the Li-ion batteries is important for the future development of new cathode materials.
Three-Dimensional Electric Micro-Grid Network for High-Energy-Density Lithium-Ion Battery Cathodes
Authors: Zettsu Nobuyuki , Kim Dae-wook , Teshima Katsuya
Published: February 2020

High-energy-density LiNi0.5Co0.2Mn0.3O2 (NCM523) cathodes are prepared by the reduction of carbon additive loading based on the self-organization of water-soluble multiwalled carbon nanotubes (MW-CNTs) into MW-CNT/NCM523 supramolecular assemblies. Field emission scanning electron microscopy reveals that the MW-CNTs homogeneously included NCM523 particles and formed a grid structure that bridges the NCM523 particles. These structural characteristics are quite different from conventional composite electrode systems in lithium-ion secondary batteries. The supramolecular assemblies enable the increase of the NCM523 particle concentration (up to 98 wt%) and tap density (up to 3.8 g cm-3), and eliminate the need for a binder. A higher C-rate capability and cyclability are achieved by improving the kinetic parameters in the composite electrode for the battery reactions. In particular, the maximum average discharge capacity based on the total mass of the composite is 171 mAh g-1 in the MW-CNT/NCM523 (98 wt%) composite electrode within the cut-off voltage range of 2.5–4.3 V (vs Li+/Li), which is much higher than that of conventional acetylene black systems (157 mAh g-1).
A Study of Esters As Co-Solvents in Lithium-Ion Batteries
Authors: Ma Xiaowei , Senthil Arumugam Rajalakshmi , Glazier Stephen , Ma Lin , Xia Jian , Dahn Jeff R
Published: February 2020

Abstract:

Higher rate capability in Li-ion batteries is always better. Using esters as a co-solvent can significantly improve the rate capability of Li-ion batteries because of their low viscosity which leads to higher electrolyte conductivity [1, 2]. However, which ester is the best to use from a cell lifetime perspective? In this work, the four esters, methyl acetate (MA), methyl propionate (MP), ethyl acetate (EA) and methyl butyrate (MB) were compared as co-solvents in the electrolytes of Li-ion pouch cells at levels from 0% to 60 % by weight. Experiments included high temperature storage, ultra high precision coulometry, high rate charge to determine the onset of lithium plating, long term cycling and isothermal microcalorimetry. In addition, Gering’s Advanced Electrolyte Model was used to compare the conductivity and viscosity benefits associated with the use of each ester. The baseline electrolytes to which the esters were added were 1.2 M LiPF6 in EC:EMC 30:70 or 1.2 M LiPF6 in EC:EMC:DMC (25:5:70 by vol%). Figure 1 shows the results of 60oC storage tests for Li-ion pouch cells containing various amounts of each of the four esters. Cells were stored at either 4.2 V, to examine the stability of the positive electrode/electrolyte interface and at 2.5 V to examine the stability of the negative electrode SEI. Figure 1 shows that of the four esters, methyl acetate is greatly preferred based on the storage testing for this Li-ion cell chemistry.

Experiments involving many Li-ion cells chemistries and the four esters will be reported. Based on this work, tradeoffs involving the use of esters have been identified and will be discussed here.

[1] M. C. Smart, B. V. Ratnakumar, K. B. Chin, L. D. Whitcanack, J. Electrochem. Soc., 157, A1361 (2010).

[2] H.-C. Shiao, D. Chua, Hsiu-ping. Lin, S. Slane, M. Salomon, J. Power Sources, 87, 167 (2000).

Figure 1. Open circuit potential versus time of Li-ion pouch cells at 60±0.1oC with different ester contents: (a-d) cells containing MA, MP, EA and MB were precharged to 4.2V; (e-h) cells containing MA, MP, EA and MB were precharged to 2.5V.

Figure 1