bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding High Capacity in Li-Rich 3d Cathode Materials
Authors: Roberts Matthew , Luo Kun , Bruce Peter G. , Hao Rong
Published: February 2020

Lithium rich layered cathodes, which offer increased capacity, have, for several years, been regarded as one of the next major advances, able to store charge by invoking transition metal and oxygen redox processes in the same material. However, they are still challenged by problems such irreversible first cycle capacity, voltage fade on cycling related to changes in the structure. Recently important work has been carried out to better understand the origin of the high capacity and the voltage fade.

In this contribution we shall present data probing the nature of the O redox states in Li rich 3d transition metal oxides, on the nature of O loss probed by isotopic substitution and on the degree of oxygen loss vs oxygen redox.  We shall also report on a new sol-gel synthesis for Li1.2Mn0.54Ni0.13Co0.13O2. The electrochemical performance is shown in Figure 1. The cycling stability of the material is good with a capacity of ~250 mAh g-1 maintained after 100 cycles.

Figure 1. Load curve and cycleability data of sol-gel prepared Li1.2Mn0.54Ni0.13Co0.13O2 at a rate of 50 mA h g-1.

Figure 1
Single Particle Approach for Structure Characterization of Solid-State Synthesized Li4Ti5O12
Authors: Pelegov Dmitry V. , Slautin Boris N. , Kuznetsov Dmitrii K. , Zelenovskiy Pavel S. , Alikin Denis O. , Kiselyov Eugene A. , Kholkin Andrei L. , Shur Vladimir Ya. , Gorshkov Vadim S.
Published: February 2020

Synthesis of any material means that the obtained product contains some volume of other phases. These impurities sometime are neutral, sometimes worsen the functional properties of the target material, and sometime can cause unwanted side reactions. In production of electrode materials for markets of electric vehicles and renewable/grid energy storages, such material heterogeneity is turned up due to drastically increasing demands in not expensive large-scale production and required decreasing of grains sizes. Wherein, despite the modern level of nanotechnology, the structural characterization is still mainly made by avaraging methods. For the first time we demonstrate that structural heterogeneity in commercial negative electrode material Li4Ti5O12 with sub-micron grain size synthesized using standard solid-state method can be described locally in terms of structural characterization of single particles. Combination of micro-Raman Spectroscopy and Scanning Electron Microscopy has allowed to consider phase transitions during solid-state synthesis from principally new angle. Proposed local approach can be used as an addition to integral techniques not only for Li4Ti5O12, but also to a wide range of commercial products.

Solid state synthesis of Li4Ti5O12 was made using chemically pure titanium dioxide TiO2 and chemically pure lithium carbonate Li2CO3by the following reaction:

2Li2CO3 + 5TiO2 = Li4Ti5O12 + 2CO2↑                                                                      (1)

Our modification of usual solid-state method, based both on analysis of intermediate reactions and review of the published data, uses three consequent synthesis stages with intermediate grinding which increased influence surface layers on material physical properties. In order to simplify other phases observation we knowingly increased the content of phase diagram nearest compositions TiO2 и Li2TO3by using partial (incomplete) synthesis with skipped third stage.

Raman spectra of single particle (Figure 1) clearly demonstrate heterogeneity of phase transformations during reaction (1) and allow making us some conclusions about the processes peculiarities which can’t be made otherwise.

Figure 1: SEM images and corresponding Raman spectra of single particles of final phase Li4Ti5O12 and two nearest phases Li2TiO3 and TiO2 rutile. SEM images sizes are 0.8×1.0 µm.

Figure 1
Development of a Modified Coin Cell for in-Situ, Long Duration Synchrotron X-Ray Powder Diffraction
Authors: Baker Annabelle , Day Sarah , Tang Chiu C.
Published: February 2020

The use of in-situ X-Ray Powder diffraction for the study of new battery materials has grown in recent years, providing an insight into the effects that charge/discharges cycles have on cathode materials. These experiments are often limited to short periods of time and therefore only allow for one full charge/discharge cycle/multiple fast cycles to be observed. The result is that material characteristics may be well understood for the first cycle but little is known about the long term processes that ultimately lead to failure of the cell over longer timescales. 

The Long Duration Experiment (LDE) Facility on Beamline I11 at Diamond Light Source is the first of its kind, housing experiments that require periodic, in-situ monitoring over periods of months to years. It is an ideal facility for the long term study of battery materials, allowing data to be collected over many cycles.  To conduct these experiments a new cell had to be developed that would allow the transmission of X-rays, while also remaining impermeable to air and moisture for a long period of time. Previous in-situ diffraction experiments of battery materials have generally involved using unconventional cells. While these are effective, they are often not stable for long periods of time and are not true representations of real-life battery systems. By modifying a standard CR2032 coin cell case, we have been able to produce a cell that fits this purpose. Laser thinning was used to reduce the thickness of a small section of the cell to 50μm, allowing sufficient X-ray transmission without compromising the integrity of the cell.
Triggering the in Situ Electrochemical Formation of High Energy Density Cathode Material from MnO
Authors: Zhang Leiting , Chen Guohua , Tarascon Jean-Marie
Published: February 2020

High energy density electrode materials are in pressing needs for next generation Li-ion batteries. While the stellar, laboratory-wise, is intercalation-type layered oxides involving both cationic and anionic redox processes,1 conversion-type fluorine-based materials are also demonstrating attractive performances owning to the multi-electron transfer and high electronegativity of fluorine. Compared to pure fluorides, metal oxyfluorides possess higher conductivity and better electrochemical activity.2 However, their performances are overwhelmingly dependent on several parameters, such as nominal composition, synthesis conditions, particle size and morphology. Recently, Kang and co-workers proposed a “redox composite” model, where a redox center (transition metal oxide/fluoride, MO/MF) and a Li+ reservoir (LiF) were blended by ball milling and directly used as the cathode.3This allows in principle countless pairs of composite electrodes to be explored as high energy density positive electrodes.

Herein, we report that manganese monoxide (MnO), who has long been believed as a promising conversion anode material based on the Mn2+/Mn0 redox couple, can indeed turn into a high energy density cathode material delivering over 200 mAh g-1 capacity with an average potential around 3 V (Fig. 1). A one-step high energy ball milling method is adopted to trigger the reactivity of nanosized MnO particles. This process does not require any sophisticated synthesis routes, and can be easily scaled up for volume production.

Interestingly, this encouraging result is achieved without any LiF addition, thus calling for further exploration and understanding of the reaction paths. Based on various characterization techniques, it is found that the electrochemical activity is deeply rooted in the electrode-electrolyte interfacial reactions, and is strongly correlated with the stability of LiPF6-based organic electrolyte. This finding raises the practical utility of such electrochemically made high capacity electrodes.   

Reference:

1   M. Sathiya, G. Rousse, K. Ramesha, C. P. Laisa, H. Vezin, M. T. Sougrati, M. L. Doublet, D. Foix, D. Gonbeau, W. Walker, A. S. Prakash, M. Ben Hassine, L. Dupont and J. M. Tarascon, Nature Mater., 2013, 12, 827–835.

2   N. Pereira, F. Badway, M. Wartelsky, S. Gunn and G. G. Amatucci, J. Electrochem. Soc., 2009, 156, A407.

3   S.-W. Kim, K.-W. Nam, D.-H. Seo, J. Hong, H. Kim, H. Gwon and K. Kang, Nano Today, 2012, 7, 168–173.

Fig. 1 First three cycles of MnO electrode cycled in LiPF6-based electrolyte.

Figure 1
Synthesis and Electrochemical Properties of Li2TMCl4 (TM=V, Cr, Fe, Mn, Co)
Authors: Vinado Carolina , Wang Shanyu , Yang Jihui
Published: February 2020

Li-rich Li2TMCl4 system (TM = V, Cr, Fe, Mn, and Co) was studied as an alternative to LiFePO4 due to its high ionic conductivity (10-5 S/cm for Li2FeCl4 at 60°C [1]), similar theoretical capacity (165 mAh/g for 1.2 Li+ out of Li2FeCl4 vs. 170 mAh/g for 1 Li+ out of LiFePO4
[2]), and higher working voltage (3.7 V for Li2FeCl4 vs. 3.4 V for LiFePO4
[1]). These cathode materials were successfully synthesized by ball milling and solid state reaction techniques, using LiCl and TMCl2as the precursors. The phase compositions were determined by X-ray diffraction and confirmed with Rietveld refinements.

Swagelok devices were designed and built for electrochemically characterization. The cathode, a mixture of the active material, carbon black, and solid electrolyte, was consolidated with solid electrolyte using spark plasma sintering (SPS). The design of the devices and techniques were validated using standard materials, such as LiCoO2 and LiFePO4purpose., as well as EIS, CV, XRD, and galvanostatic cycling tests. The standard materials were also used to compare against the performance of the Li2TMCl4 cathode material system.

Wang, C. & Hong, J. Electrochem. Solid-State Lett.
10, A65 (2007).

Whittingham, M. S. Chem. Rev.
104, 4271–301 (2004).
Simulation and Experiments on Dendrite-Free Lithium Metal Electrode Via Surface Modification
Authors: Park Joonam , Jeong Jiseon , Lee Yunju , Byun Seoungwoo , Appiah Williams Agyei , Cho Kuk Young , Lee Young-Gi , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

Lithium metal having the lowest reduction potential (-3.04 V vs. SHE) and high specific capacity (~3800 mAh g-1) have not been successfully implemented in commercial lithium secondary batteries (LSBs) due to the formation of lithium dendrite, resulting in inhibited battery performance and instability. However, to accomplish the mileage and high energy requirements of electric vehicles and energy storage systems, the above drawbacks of lithium metal need to be solved for it to be implemented in LSBs. Hence, based on our experimental findings on the dependency of current flow on metal surface morphology, we adopted a mathematical model to simulate and optimise the metal surface morphology of different shapes to locate dendrite-free regions. To reflect the simulation results, the electrochemical performance of cells assembled with and without controlled lithium metal surface was experimentally conducted. Field-emission scanning electron microscope (FE-SEM, S-4800, Hitachi) was also used to confirm dendrite formation on lithium metal surface during charge and discharge.

The simulation results showed difference in current flow according to the different shaped patterns on the metal surface. An optimized patterned surface morphology is presented to prevent the dendrite formation. From our experimental results, we found out that cells with controlled Li metal surface morphology exhibited improved long-term cycling performance. From the FE-SEM images, the pattern holes are readily filled with liquid like and granular forms of Li-metal without any dendrite growth during the Li deposition process.

References

1. M. -H. Ryou, Y. M. Lee, Y. Lee, M. Winter and P. Bieker, Adv. Funct. Mater, 25, 825-825 (2015).

2. A. Ferrese, P. Albertus, J. Christensen and J. Newman, Journal of The Electrochemicla Society, 159, A1615-A1623 (2012).

Acknowledgements

 This work was supported by the international Collaborative Energy Technology R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20158510050020).

Figure 1
A Series of Unique Carbon Materials for Lithium-Sulphur Batteries
Authors: Xi Kai , Kumar R Vasant
Published: February 2020

Lithium-sulphur (Li-S) cells are attractive electrochemical energy storage systems because of the high theoretical capacity of 1675 mAh g-1of sulphur. But low active material utilization, poor cycle life and low rate performance hinder their practicality, which arising from the highly insulating nature of sulphur, the high solubility/diffusivity of lithium polysulphides in the organic electrolyte and volumetric expansion of sulphur during lithiation.

Carbon materials with high specific surface area and the porous structure are beneficial for uniform loading and distribution of sulphur in the structure to improve the reaction of sulphur in the cathode. It is important to maintain the electrical conductivity network of carbon providing envelope for lithium sulphide reduction and oxidation within a liquid solvent electrolyte without loss of fluidity, while minimising shuttling away of sulphur and avoiding or controlling the deposition of insoluble sulphides which can block the conducting paths. In addition, porous space could accommodate the volume variation of sulphur. Therefore, sulphur-carbon composites, using porous carbon have become a key research topic in Li-S batteries. Herein, the design and preparation of a series of unique carbon materials, based on metal organic framework (MOF)-derived hierarchical porous carbon, graphene-wrapped microporous carbon composite, few-layer graphene foam and carbon nanotube forest, have been demonstrated for sulphur loading to fabricate cathode structures for Li-S batteries. The improved electrochemical performance provides novel approaches to designing and fabricating long cycle life cathodes in Li-S cells.

Reference

1.
Nano Energy, 2015, 12, 538-546.

2. Nanoscale, 2014, 6, 5746-5753.

3. APL Materials, 2014, 2(12), 124109.

4. Chemical

 

Communications
, 2013, 49, 2192-2194.
Effects of Heat-Treatment on the Properties of Spinel LiNi0.5Mn1.5O4 Cathode Materials
Authors: Wu She-huang
Published: February 2020

High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) were synthesized by a spray pyrolysis method followed by heat treatment at 900oC for 8 hours then post annealing at 700oC for varies duration (0-96 hours) under air atmosphere. The crystalline structure and morphology of the prepared samples are studied with X-ray diffraction (XRD), neutron powder diffraction (NPD), Raman spectroscopy, scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM). The electrochemical properties of the prepared materials had also been investigated by the studies of cyclic voltammetry (CV) and the capacity retention with coin-type cells by use of battery testing system. The results show all of the prepared samples have similar morphology and average particle size, but crystalize into mixtures of ordered P4332 and disordered Fd-3
m phases with various fractions. It can be found from Table 1 that the phase fraction of ordered phase obtained from the Rietveld refinement of NPD patterns increases with increasing duration of post annealing at 700oC. Fig. 1 manifests the results of cycling performance of the coin cells comprised with the prepared samples at 0.1 and 1.0 C rates, respectively. Samples containing the higher phase fraction of disordered phase exhibits the lower capacity fade than those dominated with ordered phase. It may be attributed to the ordered phase dominated sample experienced more complex phase change than the disordered phase dominant sample, which had been revealed from the in-situ NPD studies.

Figure 1
In Situ Tracking of the Structure Chemistry during the Synthesis of Ni-Rich Layered Oxides As High-Energy Cathodes for Lithium-Ion Batteries
Authors: Bai Jianming , Zhao Jianqing , Huq Ashfia , Zhang Wei , Wang Dawei , Wang Feng
Published: February 2020

Ni-rich layered oxides are potential candidates for cathodes of high energy density, and meanwhile low cost and environmental benign by reducing the usage of Cobalt.  To develop Ni-rich layered oxides as durable high-energy cathodes in lithium-ion batteries, construction of a solid solution in the transition metal layers by adding a second or even third cation into the LiNiO2 framework is becoming an effective strategy for stabilizing the structure and/or tailoring electrochemical properties. It has been reported that electrochemical performance is greatly affected by even a small amount of Ni-ion mixture in the Li-ion layers, and this kind of structural disorder can be controlled by improved synthetic protocols. In order to improve the electrochemical properties of the material it is critical to understand its structure chemistry during the high temperature synthesis process.  Herein, we report on developing new high-capacity Ni-rich cathodes with enhanced cyclability via tuning the stoichiometry and structure of the materials. Systemic investigation is made to the phase evolution of Ni-rich LiNi1-x-yMnxCoyO2 (x+y ≤ 0.3) under different annealing temperatures by in situ synchrotron X-ray diffraction (XRD) measurements, combined with neutron diffraction and transmission electron microscopy/spectroscopy. Structural characterization indicates intriguing phase transitions during the formation of LiNi1-x-yMnxCoyO2 in the high temperature annealing process, which are closely related to cation mixture. Structure related order parameters can be used to describe these phase transitions and to determine all of the phases in such a complicated Ni-Mn-Co composition space, which, however, is challenging due to their strong dependence on the Mn and Co stoichiometry (i.e. x and y values). The in-situ XRD studies gain us access to the phase diagram in the Ni-rich region of the Ni-Mn-Co space (x+y ≤ 0.3), thereby enabling the design of synthetic protocols for preparing high-capacity LiNi1-x-yMnxCoyO2 cathodes with stabilized structure and reasonable cycling stability.

The work is supported by DOE-EERE under the Advanced Battery Materials Research (BMR) program, under Contract No. DE-SC0012704.
Binder-Less Monolithic Silicon Anodes - Enevate's HD Energy® Technology
Authors: Park Benjamin Yong
Published: February 2020

Enevate's HD Energy® technology is a unique technology that utilizes film active material vs powder-form active material.  This allows for cells with high energy density, high charge rates, as well as other unique characteristics while still being acceptably inexpensive and manufacturable. The technology involves electrodes that are silicon-dominant (>50% Si instead of being majority graphite). The unique characteristics of the technology as well as test data will be presented.

This talk will discuss the novel approach of manufacturing a film of active material that is not held together with a polymer binder.  The award-winning technology (Enevate has been named a CES 2016 Innovation Awards Honoree for its unique silicon Li-ion batteries with HD-Energy® Technology in Computer Hardware & Components, Embedded Technologies, and Portable Power categories. 

Enevate has developed advanced secondary Li-ion batteries based on new anode approaches which utilize silicon as the major component (vs other approaches which utilize silicon as an additive to graphite) as well as cell designs with significantly higher volumetric (25-50% increase)and gravimetric energy density.  The cells which are in thinner and lighter form factors have the additional advantage of having significantly faster charging than current conventional Li-ion batteries. The ultrafast charging feature has been demonstrated to provide a 90% charge in 15 minutes (or 50% charge in just over 5 minutes) in high-energy cells.

Enevate is currently transitioning to manufacturing cells and packs that utilize its technology for its customers in the mobile electronics sector.  The manufacturing approach of Enevate utilizes a global "fab-light" model where Enevate is partnering with multiple manufacturing partners while handling the manufacturing of the key component in its own factory.

Figure 1
Modeling of Conductivity of Lithium Salt in Electrolytes for Lithium-Ion Batteries
Authors: Dougassa Yvon Rodrigue , Lepage David , Rochefort Dominic
Published: February 2020

The lithium ion battery is the most competitive power source for electric vehicles needed in the future, thus attracting extensive interest. The performance of a lithium ion battery depends to a great extent on the conductivity of electrolyte solution, because the conductivity of electrolyte solution is related to transport process and play an important role in field of lithium batteries as knowledge of the conductivity is necessary for the design of Li cells [1]. The conductivity provides also useful insights on ion solvation and association. We present in this work a comparative study on experimental values of conductivity of several formulated electrolytes (pure solvents, binary or ternary systems involving a lithium salt) with calculated values by modelling.

At first, by using different well-known equations based on Stock-Einstein, Jones-Dole and Bjerrum theories and of the solvent-solvent and solvent-salt interactions a model of conductivity ionic had been developed. The relative permittivity values of the electrolytes as well as the B- coefficients of the Jones-Dole equation for the relative viscosity of concentrated electrolyte solutions have been determined as a function of the temperature. Finally, the calculated values were then compared with experimental data of conductivity to evaluate the predictive capability of the model. Excellent agreements were obtained between calculations and experimental data electrolytes as a function of temperature with deviations up to (4 and 10) %. Results obtained by modeling during this work will guide the formulation of safer electrolytes able to improve the performances of lithium-ion batteries of lithium-ion batteries and the lifetime

[1] F.Blanchard, B. Carré, P.Willmann, D. Lemordant, Journal of power sources. 109 (2002) 203-213.
Thermal Decomposition Products and Pathways of Novel Organosilicon Electrolytes for Lithium-Ion Batteries
Authors: Guillot Sarah Lucienne , Pena Hueso Adrian , Usrey Monica Lee , Hamers Robert J
Published: February 2020

Conventional lithium-ion battery carbonate-based electrolytes have displayed thermal instability and decomposition, leading to performance fade and concerns about the safety of these energy storage devices. In collaboration with the University of Wisconsin, Silatronix, Inc. has developed a novel class of organosilicon solvents for battery electrolytes which have enhanced thermal stability, long cycle lifetime, and decreased electrolytic gas evolution. We have studied the thermal stability of electrolyte systems with organosilicon solvents in comparison with conventional carbonate electrolytes. We report the quantitative analysis of solution and gas phase decomposition products over the course of several weeks under conditions of high heat and artificially increased water content. Our comparative studies of carbonate and organosilicon electrolyte thermal hydrolysis include discovery of an important donor-acceptor complex, computational modeling to identify key decomposition intermediates, and the development of kinetic degradation models. These studies help us to understand what gives rise to the superior thermal stability of these electrolyte solvents.
Dynamic Electrochemical Impedance Spectroscopy-a Tool to Optimize the Operating Potential Window to Minimize the Capacity Fading
Authors: Sripada Raghu , S Ramaprabhu
Published: February 2020

Sodium is low cost and abundant resource and its distribution geographically makes it attractive over the lithium counterpart. Like graphite for lithium ion batteries, finding standard negative electrode materials for sodium ion batteries with good stability and long cycling life is still a challenge. Therefore, focus on new material and optimization of the known electrode material is important. In the present work, dynamic electrochemical impedance spectroscopy (DEIS) is used as a tool to probe the electrochemical processes occurring in these cells. In normal electrochemical impedance there is no control over the state of charge while measurement is performed. DEIS facilitates static state of charge, which will not disturb state of the cell. Therefore, we have the opportunity to perform impedance measurement during charging as well as discharging of the cell at different potential steps that will help in optimization of potential window of the cell. Hard carbon is well known insertion anode material compatible with sodium and lithium ion batteries. Therefore sodium ion and lithium ion half-cells are assembled by using hard carbon as anode material. Using DEIS and cyclic voltammetry, potential window for galvanostatic cycling is optimized which minimizes capacity fading. The optimized potential window is verified by performing galvanostatic cycling at various potential steps and correlating with DEIS. By optimizing the potential window capacity fading got reduced from 30% to 3%.
Newer Electrode Materials for Li / Na Batteries
Authors: S Gopukumar , Raman Ravikumar , Venkata Rami Reddy Boddu , Elizabeth Indu , V Selvamani
Published: February 2020

The lithium ion battery has evolved as the major power source ever since it’s discovery in 1991 by Sony and represents one of the major successes of materials electrochemistry. Lithium ion batteries are becoming more and more popular in view of the multifarious applications arising from their high voltage and high power leading to light weight and smaller size cells/batteries. In view of the growing day to day demand for lithium ion batteries, intensive research is being pursued globally to develop new high performing cost effective electrode and electrolyte materials and importantly without compromising on environmental issues.

            In this talk, we shall give an overview of the recent work being focused by tailoring the carbon materials for developing high performing anode materials based on viz., reduced graphitic oxide (rGO), graphene nano structures (GNS), multi-walled carbon nanotubes (MCNT), Bioderived and cathode materials under the national solar mission programme of CSIR.   Normally, graphite powders are employed as anode materials but we demonstrate a new type of lithium ion battery replacing the conventional graphite powder coated on to a copper foil which exhibits high performance even at high rates (2C) when cycled between 2.9 and 4.1V and finds applications in Solar Lanterns etc. These cells could be charged by solar energy. Furthermore, possible use of Sodium (Na) as an alternative to Lithium will also be highlighted.
Long Cycle Life and High Power Aqueous K-Ion Batteries
Authors: Su Dawei
Published: February 2020

The deployment of solar, wind and other volatile renewable energy sources and their integration with the electric grid needs the new types of energy storage which can provide the power, energy density and cycle life. Here we report a newly developed aqueous K-ion batteries used potassium iron hexacyanoferrate dihydrate as cathode, which are safe, inexpensive, and have superior high-rate, long cycle life electrochemical performance. The as-prepared crystalline nanocubes of potassium iron hexacyanoferrate dihydrate have a low strain open framework structure. Relying on the K+ ions insertion/extraction into/from the structure, the cathode reacts rapidly with very little hysteresis for hundreds cycling, as revealed by the electrochemical testing, ex-situ XRD, FTIR and kineticsanalyses. Most importantly, the high K+ ion content ensures its high discharge capacity (120 mA h g-1). It was also revealed the materials involves two-step redox reactions at charge/discharge plateaus of +0.92/ +0.84 V and +0.3/+0.2 V which should be ascribed to the high-spin state nitrogen-coordinated Fe3+/Fe2+-[N≡ couple and low-spin state carbon-coordinated FeIII/FeII-[C≡ couple, respectively. The open-framework structure enables structural integrity, leading to the fast kinetics and highly reversible properties (> 85 % capacity retention over 500 cycles at 21.4 C) as revealed by the experiments and DFT calculation. The low-cost, scalable, simple synthesis process and excellent electrode performance of potassium iron hexacyanoferrate dihydrate make it attractive for large scale energy storage systems
Determination of Radial Thermal Conductivity and Specific Heat in Externally-Heated LiCoO2 cells
Authors: Mazurick Ryan , Brandon Andrew , Spinner Neil , Tuttle Steven G
Published: February 2020

In this presentation, we will investigate the thermophysical properties of LiCoO2 18650 battery cells. Due to their versatility and high energy density, lithium-ion batteries have become a major power source in a number of consumer and industrial products over the last decade. As their popularity and number of applications increase, so do instances of catastrophic battery failure. Excessive external heating, which in turn leads to thermal runaway, is a principle cause of cell failure and failure events continue to occur despite the installation of safety features, such as vents and thermal fuses, within the cells. Models of cell failure do exist and they have been used to improve upon battery safety features; however, failure models require prior knowledge of the cell’s thermophysical properties.

    For many common, commercial lithium-ion batteries, LiCoO2 18650 cells included, knowledge of their thermophysical properties is often either incomplete or absent entirely. To determine the radial thermal conductivity and specific heat of a LiCoO2 18650 cell, we conducted external heating experiments and created a numerical heat transfer model.  In our experiments, a thermocouple and a heat flux sensor were mounted to the battery surface and, without damaging the cell, external heat was provided using NiCr wire, wrapped helically around the cell’s exterior. Using the time-dependent heat flux data measured at the battery’s surface, our computational model solved the heat conduction equation for the cell’s radial temperature profile. The radial thermal conductivity and specific heat of the LiCoO2 18650 cell were then found by minimizing the difference between the experimental surface temperature data and the model’s predicted surface temperature over time. Matching the model’s results with the experimental data was achieved with a parametric exploration of specific heat values and the Secant Method, which iterated over the radial thermal conductivity. Over the course of our presentation, the experimental setup, the numerical model, and the results we obtained will be explored in detail. We will also discuss how this method can be used to study the radial thermal conductivity and specific heat of any cylindrical cell.
Pseudo-Contact Shift in Periodic Paramagnetic Solids Via Density Functional Theory
Authors: Pigliapochi Roberta , Pell Andrew , Ceresoli Davide , Kaupp Martin , Grey Clare P.
Published: February 2020

Nuclear Magnetic Resonance (NMR) spectroscopy of paramagnetic solids represents an exceptional means for getting insight into structural and electronic properties of the systems, giving on the other hand a particularly involved response to analyse. Specifically, the overall isotropic shift is given by a combination of the Fermi contact term, dependent on the electronic structure of the paramagnetic site and on the strength and covalency of its bond with the observed centre, and on the pseudo-contact term, a relativistic dipolar  contribution that gives information regarding the structure and the spatial arrangements of the sites in the system. In this work we present a protocol to extend the computation of the paramagnetic shielding in the presence of spin-orbit coupling towards solid systems, with which to calculate these two contributions explicitly via periodic solid-state Density Functional Theory (DFT) so to unravel detailed information hidden in the NMR spectrum. We describe how the involved properties such as g- and hyperfine tensors behave in paramagnetic solids where the spin-bearing ions are a major constituent of the crystal lattice. Finally it is clarified how to combine these quantities in order to separate the various terms contributing to the paramagnetic shielding, σs
: this method enables to get deeper insight into the overall isotropic shift and shift anisotropy observed experimentally, and to identify information regarding electronic structure and geometry of the system. The method is applied to a series of solid-state LiTMPO4 (with TM=Mn, Fe, Co and Ni) powders and the corresponding 7Li and 31P NMR shifts are computed. From these results we outline differences in the extent of spin-orbit coupling effects and electron-nuclear magnetic interaction, and the various tensorial products are combined together to explicitly calculate all the terms involved in the description of σs
. A detailed comparison is presented between contact and dipolar interactions within the same system and across the series, to untangle the dual nature of the overall isotropic shift and shift anisotropy.
Metals Recovery from Spent Lithium-Ion Batteries: Synthesis and Physicochemical Properties of New Extractants for Solvent Extraction Processes
Authors: Omelchuk Kateryna , Haddad Mansour , Cote Gerard , Chagnes Alexandre
Published: February 2020

Cobalt, nickel, lithium and manganese are strategic metals from many applications including alloys manufacturing, electrode materials for lithium-ion batteries (LIBs), etc. Their recovery from spent materials is a good opportunity from economical and geopolitical viewpoints. Indeed, these metals are expensive and recycling will reduce considerably their supply risks in the forthcoming years due to likely emergence of electric vehicles. Therefore, recovery of cobalt, nickel manganese and lithium from LiBs is strategic and development of efficient and economic processes is coming to the fore.

Several research activities were carried out to recycle strategic metals from spent batteries by different methods such as pyrometallurgy, hydrometallurgy and biohydrometallurgy. Pyrometallurgical processes are however energy intensive and release gases like sulfur dioxide and carbon dioxide which are harmful to the environment. In recent past, metallurgical industry has been searching for hydrometallurgical processes due to some advantages such as possibility of treating low-grade resources, easier control of wastes and lower energy consumption. Hydrometallurgical processes are based on physical separation, leaching, purification, precipitation and in some cases electrowining. The demand for high purity metals and recent trends towards environmentally friendly technologies have focused more attention onto solvent extraction because this technology is mature and permits to achieve high extraction efficiency at low operating costs. Although extractant molecules are at the center of concern to achieve high efficiency and high selectivity of metal recovery in hydrometallurgical recycling processes, only few teams focus their research on the synthesis of new extractants.

In this paper, extraction properties of new extracting agents for the recovery of cobalt, nickel, manganese and lithium will be presented after a brief overview of challenges and drawbacks in the development of lithium-ion batteries recycling processes. Extraction equilibria and relationships between their chemical structures and their extraction properties will be discussed. A flow sheet will be then deduced from experimental data provided in this paper to recover lithium, cobalt, nickel and manganese from spent cathodes contained in LiBs.

A. Chagnes, B. Pospiech, "A brief review on hydrometallurgical technologies for recycling spent lithium-ion batteries”, Journal of Chemical Technology and Biotechnology 88, 1191-1199 (2013).

A. Chagnes, J. Swiatowska (Ed), “Lithium Process Chemistry: Resources, Extractions, Batteries and Recycling”, http://dx.doi.org/10.1016/B978-0-12-801417-2.00005-0, ISBN 978-0-12-801417-2, Elsevier (2015).
Electroplating Three Dimensional Lithium Ion Batteries
Authors: Zhang Huigang
Published: February 2020

The request for high energy lithium ion density batteries pushes forward the research on materials which could store more lithium atoms such as Si, Sn and so on. For example, Si and Sn could store 9786 and 7246 mAh/cm3. However, high capacity materials have the large volume changes during charge/discharge and leads to rapid degradation (Figure a). 3D scaffolded electrodes could accommodate the volume change and mitigate capacity loss. We have developed a route of fabricating 3D bicontinuous electrodes which consist of an inactive 3D scaffold and a conformal coating of active materials[1-6]. The nickel scaffold is derived from polystyrene opal templates (Figure b). Sn alloy is electrodeposited onto the 3D scaffold  (Figure c). Such a scaffolded structure could hold the active material, efficiently conduct electrons, and partly manage the stress-induced capacity decay. The electrochemical analysis confirms that the inert 3D metal scaffold could stabilize the alloy electrode and significantly improve the cyclability of high capacity anodes. With the progress in the Sn anode[4], we also applied the similar concepts to silicon and metal oxide anodes, which are coated to the scaffold by CVD and hydrothermal methods[5-6]. Summarizing the research on Sn, Si, metal oxide leads to a conclusion that well-design scaffold structure and conformal coating are two key factors which contribute to the performance improvement of high capacity anodes. 

References

[1]. Zhang, H.; Braun, P.V. Nature Nanotechnol. 2011, 6, 277.

[2]. Pikul, J.H.; Zhang, H.; Cho, J.; Braun, P.V.; King W. Nature Commun. 2013, 4, 1732.

[3]. Yu, X; Zhang, H.; Oliverio, J.K.; Braun, P.V. Nano Lett. 2009, 9, 4424.

[4] Zhang, H.; Shi, T.; Wetzel, D.J.; Nuzzo R.; Braun, P.V. Adv. Mater. 2015, DOI: 10.1002/adma.201504780

[5]. Zhang, H.; Braun, P.V. Nano Lett. 2012, 12, 2778.

[6] Liu, J.; Zhang, H.; Wang, H.; Cho, J.; Pikul, J.H.; Epstein, E.S.;  Huang, X.;  Liu, J.;  King, W.P.; Braun, P.V. Adv. Mater. 2014, 26, 7096-7101.

Figure 1
A Statistical Model of the Voltage Fade Phenomenon in Lithium-, Manganese-Rich XLiMnO3·(1-x)LiNiaMnbCocO2 Materials
Authors: Bloom Ira , Vu Anh , Qin Yan , Lin Chi-Kai , Abouimrane Ali , Burrell Anthony K. , Bloom Samuel , Bass Dean A , Bareno Javier
Published: February 2020

The effect of composition in the lithium- and manganese-rich region of (Li2MnO3)a(LiNiO2)b(LiMnO2)c(LiCoO2)d — where 0≤a≤0.83, 0.15≤b≤0.42, 0≤c≤0.85, and 0≤d≤0.30 (a + b + c + d = 1) — on the phase relations and the voltage fade phenomenon was probed using combinatorial synthesis methods.  The observed values of voltage fade indicated that it was not very sensitive to composition.  These values were found to be amenable to statistical modeling using the methods of Scheffé [1, 2].  The model indicated that it may be possible to markedly reduce voltage fade, but these potential compositions would be relatively low in lithium content and may not have the layered-layered structure.

The work at Argonne National Laboratory was performed under the auspices of the U.S. Department of Energy (DOE), Office of Vehicle Technologies, under Contract No.

DE-AC02-06CH11357. 

The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.  The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/downloads/doe-public-access-plan
In Situ Measurements of Solid Electrolyte Interphase Evolution on Silicon Electrodes
Authors: Yoon Insun , Abraham Daniel P , Lucht Brett L , Bower Allan F , Guduru Pradeep R.
Published: February 2020

We report in situ measurements of initial solid electrolyte interphase (SEI) evolution on silicon negative electrode and also the lithiation-induced silicon volume changes in lithium ion half-cells. Thin film amorphous silicon (a-Si) electrodes are designed to enable unambiguous measurement of SEI thickness evolution and silicon thickness evolution. The thin film electrode samples are assembled into a custom-designed electrochemical cell integrated with an atomic force microscope (AFM) to facilitate real time measurements. The films are subjected to two potentiostatic lithiation and delithiation cycles by applying a series of constant potential values against lithium metal, which serves as the counter and reference electrode. The thickness changes are measured after a state of equilibrium is reached at each potential value. Experiments are carried out with two electrolytes – 1.2M lithium hexafluoro-phosphate (LiPF6) in ethylene carbonate (EC) and 1.2M LiPF6 in propylene carbonate (PC) – to investigate the influence of electrolyte compositions on SEI formation and electrochemical performance. The results reveal that the predominant SEI thickness evolution occurs during the first cycle, and reaches steady values of approximately 17nm with EC electrolyte and 10nm with PC electrolyte. Despite the thinner SEI layer, capacity loss due to SEI formation is larger with PC electrolyte compared to that of EC electrolyte. Si volume change shows approximately 21% of irreversible volume expansion during the first cycle and no appreciable irreversible volume expansion was observed in the subsequent cycle. In addition, silicon volume expansion shows an approximate linear relationship with the state of charge. Volume change and capacity of silicon films show hysteresis as functions of equilibrium potential. We seek to explain such hysteretic behavior in terms of the stress-potential coupling in silicon, which shows both qualitative and quantitative agreement. Beyond the specific materials systems considered here, the in situ AFM based experimental technique developed in this work has broader applications to investigate the role of electrolyte composition in the SEI formation kinetics.

Figure 1
Spray Drying-Assisted Synthesis of Hollow Spherical Li3VO4/C Composites for High-Performance Lithium Ion Battery Anodes
Authors: Yang Yang , Li Jiaqi , He Xinyi , Wang Jing , Sun Dong , Zhao Jinbao
Published: February 2020

Recent studies showed that Li3VO4 intercalates Li-ions mainly between 0.5 ~ 1.0 V versus Li+/Li, lower than Li4Ti5O12, and at the same time can deliver a much higher theoretical capacity (~394 mAh g-1) than Li4Ti5O12 (~175 mAh g-1).[1] Therefore, Li3VO4 might be a better anode candidate for higher energy-density cell than Li4Ti5O12 as well as better safety cell than graphite.[2]  However, its low electrode kinetics and poor electronic conductivity results in large resistance polarization and poor rate performance, preventing it from being widely used.[3, 4] In this study, we developed a method to solve these two issues simultaneously. The unique hollow spherically structured Li3VO4/C (H-LVO/C) composite was synthesized via a facile spray drying process and subsequent heat treatment (as shown in Figure 1a). TEM images (Figure 1b and c) clearly reveal the hollow structure of LVO/C microspheres, and the LVO particles are coated with a layer of carbon with thickness about 5 nm.

The surfaced coated carbon layer can enhance the electronic conductivity. Meanwhile, the hollow spherical geometry of the particles is effective for increasing the wetting area for electrolyte and decreasing the Li-ion diffusion length, both are beneficial for fast charge transport. Consequently, the composite exhibits exceeding rate capability (a stable capacity of 125 mAh g-1 even at 80 C) and long-life performance with a capacity retention of 97 % (a reversible capacity of 275 mAh g-1) after 3000 cycles at 10 C.

Figure captions

Figure 1 (a) The formation mechanism of hollow spherical LVO/C composite. (b) The TEM image and (c) the HRTEM image of the H-LVO/C. (d) Long-term cycling performance of the H-LVO/C at 10 C.

References

[1]    C. K. Zhang, H. Q. Song, C. F. Liu, Y. G. Liu, C. P. Zhang, X. H. Nan, G. Z. Cao, Adv. Funct. Mater. 2015, 25, 3497.

[2]    H. Li, X. Liu, T. Zhai, D. Li, H. Zhou, Advanced Energy Materials 2013, 3, 428.

[3]    Q. Li, J. Sheng, Q. Wei, Q. An, X. Wei, P. Zhang, L. Mai, Nanoscale 2014, 6, 11072.

[4]    Z. Jian, M. Zheng, Y. Liang, X. Zhang, S. Gheytani, Y. Lan, Y. Shi, Y. Yao, Chem. Commun. 2015, 51, 229.

Figure 1
Theoretical and Experimental Studies on Stabilization of P4332-Type LiNi0.5Mn1.5O4 with Oxygen Deficiencies through the Metal-Substitution
Authors: Shiiba Hiromasa , Zettsu Nobuyuki , Kida Satoru , Nakayama Masanobu , Teshima Katsuya
Published: February 2020

Spinel-type LiNi0.5Mn1.5O4 (LNMO) have been attracted many attentions as a cathode material for 5V-level lithium-ion secondary batteries. LNMO is possibly crystalized into two different atomic arrangements (space groups). These two differences showed different characteristics. Ni/Mn ordered P4332 offers high specific energy density and disordered Fd-3m provide high electron conductivity. The origin of their electron conductivity in the Fd-3m type LNMO is strongly connected with the oxygen deficiencies in the spinel lattice, which is accompanying the reduction of Mn4+ to Mn3+. In order to realize electron conductivity enhancement of the P4332 type LNMO, we performed both theoretical and experimental studies on phase stabilities of metal-doped oxygen-deficient LiNi0.5Mn1.5O4-δ
crystalized in spinel lattices and corresponding electrochemical properties.

We point out that LiNi0.5Mn1.5-y
Cu
y
O4-δ

is the most plausible candidate which provides stable P4332 phase with oxygen deficiency. Computational studies of difference in the defect formation energies between P4332 and Fd-3m revealed that the Fd-3m became lower than that in P4332. Especially, the partial substitution of Cu2+ with Mn4+ effectively contributed to reduce oxygen vacancy formation energy in P4332, comparing to that of Fd-3m. In addition, Mn3+ is absent when oxygen vacancy concentration is equivalent to Cu2+ concentration, even though oxygen deficiency was formed in the spinel lattice. P4332 type LiNi0.5Mn1.5-y
Cu
y
O4-δ
potentially responsible to offer no appearance of plateau at 4 V in the charge-discharge profiles, no dissolution of Mn3+ species during the charge-discharge cycling and improve electronic conductivity due to the d-electron doping by Cu2+ substitution.

Based on our theoretical calculation, we performed the flux growth of LiNi0.5Mn1.5-y
Cu
y
O4-δ

crystals. X-ray diffraction pattern and Raman spectroscopy revealed that the substation of Cu2+ highly stabilized the P4332 type LiNi0.5Mn1.5-y
Cu
y
O4-δ
. The galvanostatic charge-discharge tests at 25 ̊C, ranging from 3.5 and 4.8 V of cut-off voltage showed the appearance of flat plateau at 4.7 V attributed to Ni2+/4+ redox couple. The discharge capacities were 137 mAh g-1 at 0.2C rate and 100 mAh g-1 at 10C rate, respectively. Furthermore, no current peaks from the Mn3+/4+ redox couples were observed at 4 V by cyclic voltammetry measurements. These findings strongly suggest that the substitution of Cu2+ with Mn4+ LNMO stabilize P4332 type structure even though the oxygen deficient may contain in the spinel lattice.

Acknowledgement

This work was partially supported by CREST, JST.