bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peltier Heats of LiFePO4 electrodes from a Thermoelectric Cell
Authors: Gunnarshaug Astrid Fagertun , Kjelstrup Signe , Bedeaux Dick , Burheim Odne Stokke , Vie Preben J. S. 
Published: February 2020

Temperature is known to affect ageing and performance of lithium ion batteries [1]. We need to improve the understanding of the heat sources in the electrode compartments in order to accurately model internal temperature profiles. Reports of reversible heat effects local to electrode surfaces in lithium-ion batteries are therefore important, but are scarce in literature [2].
The reversible heat production at a battery electrode interface is investigated in this experimental work, measuring the Peltier heat of the electrode LiFePO4 electrode. The Peltier heat at an electrode can be found by measuring the change in electric potential across the cell with two identical electrodes when a temperature difference is applied [3]. We present the Seebeck coefficient and Peltier heat of a symmetric pouch cell consisting of two commercial LiFePO4 electrodes and a 1M LiPF6 and Ethylene Carbonate (EC) /Diethyl Carbonate (DEC) (50:50 w%) electrolyte-soaked separator. The electrodes have been thermostatted to the wanted temperatures T and T+ ΔT, respectively.
Al (s,T) | LiFePO4 (s,T) | EC, DEC, LiPF6 | LiFePO4 (s,T + ΔT) | Al (s,T+ ΔT)
We show that the thermoelectric effect is time-dependent due to a build up of concentration gradients within the cell, and the establishment of not only one, but two Soret equilibria. The initial Seebeck coefficient gives the Peltier heat of one electrode for a homogeneous electrolyte in a battery [4]. We derive equations that will describe the approach of the cell to steady state, and use this to estimate the initial value. The consequences of the Peltier heat of LiFePO4 for battery discharging and charging will be discussed.

Acknowledgment

The authors are grateful to the Research Council of Norway through its Centres of Excellence funding scheme, project number 262644, PoreLab. We acknowledge ENERSENSE for financial support. The group of authors also acknowledge the Research Council of Norway (RCN) project no. 228739, for funding through the project "Life and Safety for Li-ion batteries in Maritime conditions (SafeLiLife)".
References
[1] J. Vetter, P. Novak, M. Wagner, C. Veit, K.-C. Möller, J. Besenhard, M. Winter, M. Wohlfahrt-Mehrens, C. Vogler, ´ A. Hammouche, Ageing mechanisms in lithium-ion batteries, J. Power Sources 147 (12) (2005) 269 – 281.
[2] Frank Richter, Astrid Gunnarshaug, Odne Stokke Burheim, Preben J. S. Vie, and Signe Kjelstrup. Single Electrode Entropy Change for LiCoO2 Electrodes. ECS Trans., 80(10):219-238, 2017.
[3] K. S. Førland, T. Førland, and S. Kjelstrup. Irreversible Thermodynamics: Theory and Applications. Tapir, Trondheim, 2001.
Correlating Directly Recycled Cathode Performance to Aging Conditions
Authors: Wang Han , Whitacre Jay 
Published: February 2020

Traditional recycling of lithium-ion battery cathode materials draws the most attention currently due to the valuable metal elements contained, especially cobalt. There are three dominate recycling approaches that may be used to recover useful materials from the aged cathode powders: pyrometallurgical, hydrometallurgical and direct physical.(1-3) The former two methods are already operating at scale. However, they suffer from significant energy input and complex chemical process respectively, which makes the recycled products less environmental-friendly and economically competitive. Recently, processing methods have been developed with less energy and cost input by making directly recycling the cathode material for reuse in a new battery. This is appealing in cases where there is a large amount of identical or very similar cathode materials in use. (2, 4)
In this work, we show “direct recycled” products of differently cycled Li(NixCoyAlz)O2 cathode via a solid-state processing method with different parameters. We assess the materials product performance in terms of electrochemical specific capacity, phase purity and consistency. Furthermore, we correlated interaction among aged conditions of cathode, solid-state process parameters and recycled product performance. Figure 1 shows that when treated with the same solid-state process parameters, the recycled cathode materials show different electrochemical performance depending on conditions of the aged cathode materials.
In this talk, we will discuss our approach and results, as well as suggest a technical path forward for the implementation of large-scale direct recycling of cathode materials from aged lithium-ion batteries.
Reference:

L. Gaines, Sustain Mater Techno, 17 (2018).

H. Wang, S. Frisco, E. Gottlieb, R. Yuan and J. F. Whitacre, J Power Sources, 426, 67 (2019).

R. E. Ciez and J. F. Whitacre, Nat Sustain, 2, 148 (2019).

H. Wang and J. F. Whitacre, Energy Technol-Ger, 6, 2429 (2018).

Figure 1
Investigating the Electrochemical Effect of Core-Multi Shell Structured Nickel-Rich NMC Cathode Materials
Authors: Chung Youngmin , Shin Youngho 
Published: February 2020

Nickel-rich nickel manganese cobalt (NMC) oxide is a high energy density cathode material for lithium-ion batteries. However, surface-related fast capacity fading has been a major obstacle to its practical application. In this work, to address this issue, nickel-rich core-multi shell structured NMC oxide Li[Ni0.9-x-yMn0.05+xCo0.05+y]O2 (x and y ≤0.15) materials with multiple outer layers of stable NMC compositions were synthesized via co-precipitation method using a specially developed continuous stirred-tank reactor (CSTR).
We have used scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) with cross-sections of the grided particle samples, and inductively coupled plasma mass spectrometry (ICP-MS) to understand the contribution of core and outer shell layers and total composition of the synthesized core-multi shell structured NMC materials. The synthesized cathodes consisted of high-nickel NMC90/5/5 (LiNi0.9Mn0.05Co0.05O2) core and NMC333, NMC622, and NMC811 outer shells have an overall composition of NMC811 or NMC622 depending on outer shell ratio.
The analyzed concentration distribution inside the particles indicates that the nickel composition decreases linearly from the center of the particle to the surface and that the manganese and cobalt concentrations increase. The NMC811 and NMC622 of the core-multi-shell structure with optimized outer shell layer improve cycling capacity, capacity retention (92% after 100 cycles) and rate capability as compared to commercial materials having the same overall composition due to the unique microstructure of the stabilized particle surface by increasing the stable Mn4+ ratio at the shell. Electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC) results showed that the high stability of core-multi shell structured NMC materials is responsible for the reduction in surface and charge transfer resistance by decreasing the reaction with the electrolyte.
(Invited) Functional Binders for Li-, Na-, and K-Ion Batteries
Authors: Komaba Shinichi , Horiba Tatsuo , Kubota Kei , Fukunishi Mika 
Published: February 2020

A conventional binder for powdery composite electrodes, poly(vinylidene fluoride) (PVdF), is widely used in commercial lithium-ion electrodes because of its chemical and electrochemical stability and good affinity to the electrode and electrolyte materials. However, coverage of active material surface and adhesive strength of a composite layer onto a current collector are not enough to cope with severe conditions of electrode operation such as high potential or large volume change during a charge-discharge cycle. In addition, N-methyl-2-pyrrolidone (NMP) as solvent to dissolve PVdF binder to prepare electrode slurry is combustible and harmful. Since there has been intensive preference for alternative water-soluble polymer to PVdF binder, we study water-soluble polymers as new binders for lithium-ion cells, being convinced that binder is critical materials to maximize the intrinsic performance of active materials and to modify the negative electrode surface including SEI to suppress undesired side-reactions at graphite electrode [1]. Recently, we extend our work on binder towards cross-linked and natural polymers for negative and positive electrodes for Li, Na, and K batteries. We will present detailed results to realize high-energy electrode performance with new binders such as polyacrylates [2-4], covalently crosslinked polyacrylates [5], branched polysaccharides [6], polyglutamates [7,8], and SBR latex [9]. We will also discuss the mechanism of better performance compared to that for conventional PVdF with characterization data and surface analyses.
References:
[1] S. Komaba et al., ECS Trans, 11 (29) 63-70 (2008).
[2] S. Komaba et al., J. Power Sources, 189, 197 (2009).
[3] Z.-J. Han, S. Komaba, et al., Phys. Chem. Chem. Phys., 17, 3783 (2015)
[4] M. Fukuknishi, K. Kubota, T. Horiba, S. Komaba et al., Electrochem., 87, 70 (2019).
[5] S. Aoki, S. Komaba, et al., J. Electrohem. Soc., 162, A2245 (2015).
[6] M. Murase, S. Komaba, et al., ChemSusChem, 5, 2307 (2012).
[7] T. Mochizuki, T. Horiba, S. Komaba, et al., ACS Sustainable Chem. Eng., 5, 6343 (2017).
[8] Y. Yoda, K. Kubota, T. Horiba, S. Komaba, et al., ACS Appl. Mater. Interfaces, 10, 10986 (2018).
[9] N. Yabuuchi, S. Komaba et al., J. Electrochem. Soc., 162, A538 (2015).
Effects of Esters Used in Liquid Electrolyte for Li(Ni0.6Mn0.2Co0.2)O2/Graphite Pouch Cells Under Fast Charging
Authors: Wu Xianyang , Liu Tianyi , Zhao Kejie , Lin Feng , Wood David L. , Belharouak Ilias , Du Zhijia 
Published: February 2020

Electrolyte plays a critical role in lithium ion batteries (LIBs) as it determines the ion conductivity and dictates the formation of solid electrolyte interphase (SEI)1. Typically it consists of cyclic carbonate and linear carbonate, and it is believed via combination of cyclic carbonate possessing high polarity and dielectric constant but high viscosity while linear carbonate with low polarity, low dielectric constant and lower viscosity, the mixed solvent will provide satisfactory performance.
Nowadays urgent needs for high performance LIBs from electrical vehicles (EVs) industry propel the development of LIBs capable of fast charging, and addition of esters possessing lower viscosity2,3 into the commonly used liquid electrolyte as cosolvents is considered as a possible solution to this problem. Herein performance of esters including Ethyl Acetate (EA), Methyl Acetate (MeOAC) and Ethyl Formate (EF) are investigated via cycling tests.
Firstly, physical properties (viscosity, ion conductivity and transfer numbers) of the blended electrolyte systems, consisting of 1.2 mol/L LiPF6 solvated in EC/EMC/Esters (30:50:20 wt%) are studied. Experimental results clearly show the improvement of ionic conductivity with adding the four esters compared to baseline electrolyte (1.2 mol/L LiPF6 in EC/EMC. For viscosity, the electrolytes with ester co-solvents all have lower viscosity than the baseline electrolyte over all the salt concentrations. Cycling tests are also performed for 520mAh Li(Ni0.6Mn0.2Co0.2)O2/graphite pouch cells between 2.8V-4.2V at 30°C. The cells were charged at 4C (charging ends at 15 minute) and discharged at 1C, and the result is shown in Figure 1. The cell performance and analysis will be presented during the meeting.
References:
[1] Xu, Kang. "Electrolytes and interphases in Li-ion batteries and beyond." Chemical reviews 114.23 (2014): 11503-11618.
[2] Ma, Xiaowei, et al. "A study of highly conductive ester co-solvents in Li [Ni0.5Mn0.3Co0.2] O2/Graphite pouch cells." Electrochimica Acta 270 (2018): 215-223.
[3] Smart, M. C., B. V. Ratnakumar, and S. Surampudi. "Use of organic esters as cosolvents in electrolytes for lithium-ion batteries with improved low temperature performance." Journal of The Electrochemical Society 149.4 (2002): A361-A370.
Figure 1. Cycling performance for the 4 blended electrolyte using EF, MeOAC, EtOAC and DMC

Figure 1
Tracking Battery Swelling in Uncompressed Li-Ion Cells Via in-Operando X-Ray Radiography and Micro-Tomography
Authors: Fahy Kieran F. , Shafaque Hisan Waleed , Shrestha Pranay , Ouellette David , Ge Nan , Ikeda Nobuhisa , Kotaka Toshikazu , Tabuchi Yuichiro , Bazylak Aimy 
Published: February 2020

Li-ion battery swelling during cycling is known to be a major cause of battery electrode degradation and can contribute significantly to cell failure [1,2]. The main cause of battery swelling is due to the intercalation of Li into the carbon and LiCoO2 electrodes. This swelling is known to occur anisotropically due to the electric field and Li salt distributions in the electrode [3].
We have used x-ray radiography and µCT to map this swelling, in-operando under charge and discharge conditions, in the layers of an uncompressed Li-ion battery. This study gives insight into the relationship between the battery state of charge and the electrode swelling. The change in swelling due to the electrode geometry is also investigated.
Li-ion pouch cells were cycled at 0.5, 1 and 2 C while undergoing x-ray radiography and tomography at the BMIT beamline of the Canadian Light Source. Synchrotron radiography allowed the tracking of the electrode swelling in two dimensions with high temporal (10 s/frame) and spatial resolution (3 µm/pixel). µCT measurements of Li-ion cells were carried out under the same battery cycling conditions and scans were taken at 0, 25, 75 and 100 % state of charge (3 µm/pixel, 225 s/scan). Reconstruction and segmentation of the collected images allowed for the measurement of each electrode volume.
From these results it appears that electrode swelling depends on a number of factors, including electrode geometry, charge/discharge rate and battery age. There is also a noticeable degree of irreversibility in the swelling of the electrode, which may be a possible metric for battery degradation. The quantification of the carbon electrode swelling corresponds closely with the theoretical value for lithium intercalation to LiC6, although there is a discrepancy between the swelling value obtained for the LiCoO2 electrode and theory.
These results give a valuable insight into the mechanical dynamics of Li-ion batteries under in-operando conditions and will provide validation to, and data for, battery models including stress-strain and degradation models.
References

Bond, T., Zhou, J., & Cutler, J. (2017). Electrode Stack Geometry Changes during Gas Evolution in Pouch-Cell-Type Lithium Ion Batteries. Journal of The Electrochemical Society, 164(1), A6158–A6162.

Chen, C., Wei, Y., Zhao, Z., Zou, Y., & Luo, D. (2019). Investigation of the swelling failure of lithium-ion battery packs at low temperatures using 2D/3D X-ray computed tomography. Electrochimica Acta, 305, 65–71.

Zhang, N., & Tang, H. (2012). Dissecting anode swelling in commercial lithium-ion batteries. Journal of Power Sources, 218, 52–55.

Figure 1 (a) 2D x-ray radiography of a Li-ion pouch cell and (b) 3D reconstruction of a µCT of a Li-ion pouch cell section.

Figure 1
Probing the Chemical and Structural Stability of Oxide Cathodes Using a Surface Model Reaction
Authors: Waters Crystal K , Lin Feng 
Published: February 2020

As the demand for batteries grows, there is a need for scientists to catapult efforts into further understanding surface structure and electronic properties in Li-based, layered transition metal oxide (TMO) materials. This research hypothesizes potential surface oxygen and electron transfer pathways by using benzyl alcohol oxidation as a model surface reaction.
There are many opposing theories that arise about the mechanism by which oxygen and electrons are transferred between the cathode and electrolyte. To fill the knowledge gap, a common Li-based TMO was explored using extensive X-ray spectroscopy and electron microscopy analysis to investigate the structure – activity relationship. The work proposed assists in (1) designing a model to study oxygen pathways by using a surface probe reaction, (2) determining surface electronic changes after probing, and (3) hypothesizing a mechanism for the oxygen transfer at the oxide cathode surface. This study provides a chemical basis for improved battery materials design. Conclusions from this work will assist in rationalizing the cathode-organic molecule interactions. In efforts to promote green chemistry methods, this work also hypothesizes avenues to repurpose recycled battery materials in catalytic regimes.
Electrochemical Performance of AlF3-Coated LiNi0.5Mn1.5O4 5-V Cathodes at Elevated Temperature
Authors: Lin Jeng-Yu , Chu Ching-Teng 
Published: February 2020

In the past decade, rechargeable lithium-ion batteries (LIBs) are acknowledged as one of the most suitable energy storage devices due to their high energy density, excellent cyclic performance, high power density, environmentally friendly and high operation voltage conditions. However, the development of LIBs with high energy density, high rate capability and reasonable lifetime is of great importance to meet their growing applications from portable gadgets to electric vehicles (EVs), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicle (PHEV). Up to date, LiNi0.5Mn1.5O4 (LNMO) has been regarded as one of promising cathode materials due to its high and flat working potential at around 4.7 V Vs Li/Li. The high working potential of LNMO corresponds to the high energy density and it exhibits the 658 Wh Kg-1 which is significantly higher than that of the that of LiMn2O4 (440 Wh kg-1) or LiFePO4 (591 Wh kg-1). However, the main issue of high-voltage spinel LNMO is its limited cycle life, especially at a high temperature, which is triggered by decomposition of electrolyte or dissolution of Mn/Ni at high operating potential.
In the present investigation, the surface modification of LNMO cathode materials was conducted by coating with thin layer to suppress the electrolyte decomposition and transition metal dissolution at high voltage. The surface morphology and crystal structure of the AlF3-coated LNMO were systemically investigated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) equipped with an energy-dispersive X-ray spectroscope (EDS). According to the series of electrochemical studies, it is found that the introduction of AlF3 conductive coating layer significantly enhanced the rate and cycle life of the LNMO spinel cathode than the pristine LNMO cathode, especially at elevated temperature. The optimum loading of AlF3 layer on LNMO surface was found to be 1 wt.%. The 1 wt.% AlF3-coated LNMO can maintain a stable discharge capacity of 100 mAh g-1 even after consecutive charging/discharging for 50 cycles at 0.1 C at 55oC.
Direct Observation of Electrochemically Active Fe3+/Fe4+ in LiCo0.8Fe0.2MnO4 By in Situ Mössbauer and in Situ X-Ray Absorption Spectroscopy
Authors: Indris Sylvio , Dräger Christoph , Ehrenberg Helmut 
Published: February 2020

The usage of Fe at high oxidation states might be interesting for increasing the energy density of Li-ion batteries and also for substituting expensive/toxic elements in the cathode materials. The redox activity of Fe3+/Fe4+ in the spinel LiCo0.8Fe0.2MnO4 has been investigated via in situ Mössbauer spectroscopy and in situ X-ray absorption spectroscopy (XAS) during electrochemical cycling in a complete Li battery cell [1]. The initial Mössbauer spectrum consists of a doublet with isomer shift IS = 0.330(1) mm/s and quadrupole splitting QS = 0.722(1) mm/s (Fig. 1). These parameters are characteristic of Fe3+ in a high-spin state on the octahedral sites of the spinel structure. In the beginning of the charging process vs. Li+|Li, a broadening of this doublet can be observed. This corresponds to an increased electric field gradient at the site of the Fe nuclei, i.e. an increase of structural disorder around the Fe ions, and is probably cause by the initial oxidation of Co.
During further charging, the Fe3+ doublet successively disappears and is replaced by a new narrow doublet with isomer shift of -0.134(6) mm/s. This negative value clearly reveals that Fe4+ is formed. Further cycling between 5.3 V and 4.3 V reveals that this oxidation is highly reversible.
The XAS spectra acquired during charging of LiCo0.8Fe0.2MnO4 vs. Li+|Li clearly show a shift of the Fe K absorption edge towards higher binding energies and thus an oxidation of Fe3+ to Fe4+. The XAS spectra acquired during discharging show again that this process is fully reversible.
In summary, the reversible formation Fe4+ was clearly observed by both methods, hence proving the electrochemical activity of Fe at voltages above 5 V vs. Li+/Li. This enables future research on new environmentally benign and inexpensive electrode materials with operating voltages above 5 V and thus an increased energy density.
[1] Observation of Electrochemically Active Fe3+/Fe4+ in LiCo0.8Fe0.2MnO4 by in situ Mössbauer Spectroscopy and X-Ray Absorption Spectroscopy,
C. Dräger, F. Sigel, R. Witte, R. Kruk, L. Pfaffmann, V. Mereacre, M. Knapp, H. Ehrenberg, S. Indris, Phys. Chem. Chem. Phys.
21, 89-95 (2019).
A New Method to Study Depth Profiles in Silicon/Carbon Composite Electrodes
Authors: Richter Karsten , Waldmann Thomas , Kasper Michael , Pfeifer Claudia , Memm Michaela , Axmann Peter , Wohlfahrt-Mehrens Margret 
Published: February 2020

Si as active material has become a prominent candidate as anode material for high-energy Li-ion cells. Unfortunately, Si in Si/C anodes is hard to quantify by established methods, e.g. with ICP-OES no depth profile can be obtained and HF is needed for digestion.
Here, we present a semi-quantitative depth profiling method based on glow discharge optical emission spectroscopy (GD-OES). The GD-OES calibration covers Si contents in the range of 0-100 wt.-% in the anode. The results are validated with lab and pilot line coated anodes with known Si contents. The quantified depth profiles with different pristine anodes show a homogeneous distribution of Si and therefore the presented GD-OES method is capable of assessing the quality of composite active materials, from graphite dominant up to pure Si1.
The GD-OES method is further applied to anodes obtained from Post-Mortem analysis of commercially available 18650 and 21700 cells. The measurements reveal that the anodes of state-of-the-art Li-ion cells contain up to 5% wt.-% Si.
GD-OES depth profiles of anodes after formation (anodes coated in our labs as well as anodes from commercial cells) show a Si peak near the anode surface (near the anode | separator interface, see Figure 1a. This peak changes with aging and is decreased when the anodes are washed with DMC (see Figure 1b). The presence of this peak is further investigated by EDX of ion milling cross-sections. ICP-OES of the DMC washing solution indicates soluble Si species. This aging mechanism is further investigated by Raman spectroscopy.

Acknowledgement:

The research leading to these results has been performed within the project LIB.DE and received funding from the federal ministry for economics and energy Germany (BMWi) under contract n° 03ET6081A.

Literature:

K. Richter, T. Waldmann, M. Memm, M. Kasper, and M. Wohlfahrt-Mehrens, J. Electrochem. Soc., 165, A3602–A3604 (2018).

Figure 1