bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Changes in NCM523//Graphite Cells Resulting from High-Voltage Cycling
Authors: Gilbert James A , Klett Matilda , Bareno Javier , Miller Dean , Maroni Victor A. , Abraham Daniel P
Published: February 2020

High-energy electrochemically-active materials are urgently needed to increase the energy density of lithium-ion batteries for vehicular applications. Layered-oxides are promising high-energy positive electrode materials. However, the performance of full cells containing these oxides degrades faster when cycled to high potentials (> 4.3 V w/graphite negative electrodes). In order to understand the origin of this performance loss, we conducted extensive aging tests in 2032-type coin cells and reference electrode (RE) cells. The observations and conclusions of our various tests will be highlighted during this presentation.

The coin cells in this study contain 1.6 cm2 area Li1.03(Ni0.5Co0.2Mn0.3)0.97O2-based (NCM523) positive and a graphite-based negative electrode (Gr); the electrolyte  is 1.2M LiPF6 in EC:EMC (3:7 w/w) electrolyte (Gen 2). The reference electrode cells contain 20.3 cm2 area NCM523-positive and Gr-negative electrodes, two Celgard 2325 separators enveloping a LixSn RE, and a Li-metal RE external to the electrode sandwich. Cell cycling includes formation cycles followed by aging cycles; pulse-power and AC impedance measurements are made periodically throughout the cycling.

The Li-metal RE provides information on the positive and negative electrode potentials during full cell cycling; such information cannot be obtained from the coin cell data.  For example, during cell formation, when the full cell is cycled between 3.0 and 4.4 V, the positive electrode cycles between 3.67 and 4.46 V vs. Li/Li+ and the negative electrode cycles between 0.67 and 0.06 V vs. Li/Li+. The electrode cycling potential ranges change during cell aging. Furthermore, electrode impedances measured with the LixSn RE also change during aging. We will highlight the reasons for these changes during the presentation.

In addition to the electrochemistry results we will discuss data obtained by various diagnostic techniques that include the following: Scanning electron microscopy, Raman spectroscopy, and X-ray diffraction. Our mechanistic understanding of the capacity fade and impedance rise of the NCM523//Gr cells will be discussed through these various data.

Acknowledgments

This document 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. Financial support from the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, is gratefully acknowledged. Use of the Center for Nanoscale Materials and the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

Figure 1
Investigation of MnFeO3/Multiwalled Carbon Nanotubes Composite As Potential Anode for Lithium-Ion Batteries
Authors: Chandra Sekhar Bongu , Ragupathi Jeevani , Kalaiselvi Nallathamby
Published: February 2020

MnFeO3, explored for its application in sensors, catalysis and semiconductors has been validated for the first time as anode for lithium-ion batteries, facilitated through the formation of composite containing multiwalled carbon nanotubes. MnFeO3 nanoparticles, derived from combustion method upon sonication with multiwalled carbon nanotubes (MWCNT) form MnFeO3/MWCNT composite that has been explored for the first time as anode material in lithium-ion battery applications. Scalable and highly reproducible sonochemical process has been adopted to form the composite, wherein the interweaved MWCNT ensures better electronic conductivity and the desirable pinning of pristine MnFeO3 particles with a conductive coating.  The observed capacity and rate capability behavior of MnFeO3/MWCNT composite anode are  found to be superior than pristine MnFeO3 anode in such a manner that a steady state reversible capacity of 840 mAh g-1 has been obtained at 0.5 A g-1 even after 50 cycles against an inferior capacity of 200 mAh g-1 offered by MnFeO3. Further, MnFeO3/MWCNT composite anode shows excellent rate capability and reversibility with respect to various current density conditions ranging from 0.5 to 10 A g-1, wherein appreciable capacity values of 2960 and 410 mAh g-1 have been obtained at 0.5 and 10 A g-1 respectively. The impressive electrochemical performance of MnFeO3/MWCNT composite anode could be correlated to the multifarious advantages offered by MWCNT, such as increase in the electronic conductivity, maintenance of structural stability upon cycling and mitigation of inherent and exorbitant volume changes observed upon cycling. In particular, the synergistic effect of conversion cum redox reaction triggered electrochemical activity of MnFeO3 and the increased electronic conductivity rendered by the conducting carbon network of MWCNT, possessing larger surface area and appreciable mechanical strength contributes to the improved electrochemical behaviour, observed with the currently prepared MnFeO3/MWCNT anode in a significant manner. These results suggest that the currently synthesized MnFeO3/MWCNT nanocomposite anode could be considered as a promising candidate for next generation hybrid energy storage applications. The present study is bestowed with the identification and demonstration of earth abundant, environment friendly and low cost metals viz., Mn and Fe based composite anode for high capacity and high rate lithium-ion battery applications, which is noteworthy.
Electrochemical Preparation of Fe2O3 Nanorods/Carbon Nanofiber Free-Standing Anode for Lithium Ion Batteries
Authors: Park Yiseul , Oh Misol , Baek Seong-Ho , Kim Jae Hyun
Published: February 2020

Fe2O3 nanorod/carbon nanofiber (CNF) composites were prepared by the electrochemical deposition of Fe2O3 on a web of CNFs, which was then used as a free-standing anode. The conductive, three-dimensional structure of the CNF web allowed for the electrodeposition of the Fe2O3 nanorods, while its high conductivity made it possible to use the composite as a free-standing electrode in lithium-ion batteries. A free-standing electrode, which does not use polyber binder, substrate, and conductive additive, prevented a recution of rate-capability owing to the non-conductive polymer binder. In addition, it was easy and cheap to fabricate by a simplification of a process of cell preparation. The nanorod-like Fe2O3 structures could only be electrodeposited on the CNFs; flake-like Fe2O3 was formed on flat conductive glass substrates. It can be attributed to the different growth mechanism of Fe2O3 on the CNFs because of the large number of reaction sites on the CNFs, differences in the precursor concentration and diffusivity within the CNF web. The formation of aggregates of the Fe2O3 particles on thicker CNFs also indicated that the CNFs had determined the Fe2O3 growth mechanism. The synthesised Fe2O3/CNF composite electrode exhibited stable rate capacities at different current densities. This suggested that CNF-based composite did not exhibit the intrinsic disadvantages of Fe2O3. Finally, carbon coatings were deposited on the Fe2O3/CNF composites to further improve their electronic conductivity and rate capability. The strategy adopted in this study of using a web of CNFs as the substrate for the electrodeposition of Fe2O3 and of using the resulting composite material as a free-standing electrode  or LIBs should also be applicable in the case of other metal oxide/CNF composites.
Li4Ti5O12/N-Doped Graphene Microspheres As High Rate Anode Materials for Lithium Ion Batteries
Authors: Jeong Jun Hui , Youn Hee-Chang , Choi Yeon Jun , Park Byung-Hoon , Kim Kwang-Bum
Published: February 2020

Spinel Li4Ti5O12(LTO) has been demonstrated to be one of the most promising electrode materials for lithium-ion batteries due to flat voltage range (1.55V vs. Li/Li+), high reversible capacity (175 mAhg-1), and good cyclability during charge/discharge processes.

However, the electrochemical performance of LTO deteriorates with increasing charge/discharge rates due to its low electronic conductivity (10-9 Scm-1). Several strategies, such as particle size reduction to nanoscale, metal doping, surface modification and carbon coating, and formation of composite with carbonaceous materials, have been developed to enhance the electrochemical performance.

Especially, metal oxide with carbonaceous materials provides a high electrical conductivity, which can allow lithium ions and electrons to have an access readily to reaction sites of the metal oxide. Compared to other carbonaceous materials such as graphite, carbon black, and carbon nanotube, graphene a single layer of carbon atoms tightly packed in to a 2-dimensional honeycomb sp2 carbon lattice, has attracted a rapidly growing research interest owing to high conductivity (104 Scm-1), high surface area (2630 m2g-1) and good mechanical properties. Additionally, the electrical conductivity of graphene could be modified by nitrogen doping.

As mentioned above, LTO has poor electronic conductivity. Herein, we describe a novel strategy for the fabrication of LTO/N-doped Graphene microsphere composite by spray-drying method and annealing process. It makes micro N-graphene microsphere stuffed with LTO particles. The key strategy is to create a network between N-graphene and LTO particles, and the N-graphene can be embedded into the LTO materials to greatly improve the surface conductivity. The reversible capacity, especially rate performance of the LTO/N-doped Graphene microsphere in comparison with the bare LTO and LTO/graphene microspheres were evaluated.

Experimental results indicate that the LTO/N-doped Graphene microsphere can indeed deliver enhanced rate capability and good cyclic stability. Detailed synthetic procedure and electrochemical properties of LTO/N-doped Graphene microsphere will be presented at the meeting.
Free-Standing Oxide Nanotube Array Electrodes for High Energy Density and Power Density Li-Ion Batteries
Authors: Wei Wei , Björefors Fredrik , Edström Kristina , Nyholm Leif
Published: February 2020

During the past few years, with the increasing power demand generated by applications from portable devices to electric vehicles, more and more emphasis is put on manufacturing high energy and power density Li-ion batteries, i.e., to maximize the capacities while retaining a high rate capability. So far, the studies have been mainly dedicated to the development of powder type electrode materials and relatively little attention has been paid to studies of other electrode architectures. While composite electrodes containing a mixture of the active material powders, binders and conductive additives still are commonly used, such electrodes often yield poor material utilization, undefined material/component arrangements and a lot of complex interfaces. In the present work, we demonstrate that various highly ordered, free-standing oxide nanotube array electrodes, fabricated by electrochemical anodization approaches, can be used either for high energy density and power density Li-ion microbattery applications or as model monolithic electrodes for electrode engineering studies. By using anatase TiO2 nanotube electrodes (as an example of an intercalation type material), an areal capacity of 0.37 mAh cm-2 (i.e., 40 mAh g-1) at a rate of 10C (using a (dis-)charge  current density of 9 mA cm-2), and 1 mAh cm-2 (i.e., 91 mAh g-1) at a rate of C/5), can be achieved. [1] Well-defined monolithic anatase TiO2 nanotube electrodes with fine-tuned nanotube size gradients (including tube length, diameter and wall thickness) can also be manufactured using a bipolar electrochemistry approach. [2] The gradient nanotube electrodes can provide excellent rate performance, with capacities from of 0.16 mAh cm-2 or 169 mAh g-1 at a rate of C/5 to 0.04 mAh cm-2 or 42 mAh g-1 at a rate of 50C. In addition, free-standing Nb2O5 nanotube electrodes, which can be cycled for 10000 cycles with only a 20% loss of initial capacities, can provide unprecedented high-rate battery performances, i.e. the capacities from of 0.1 mAh cm-2 or 110 mAh g-1 at a rate of C/5 to 0.04 mAh cm-2 or 44 mAh g-1at a rate of 100C.[3] Some recent work carried out to investigate highly ordered Fe3O4 nanotubular/nanoporous electrodes as a prototype free-standing conversion electrode will also be described.  References:[1] W. Wei, et al.,  submitted, 2015 ; [2]  W. Wei, et al., Electrochim. Acta 2015, 176, 1393 ; [3] W. Wei, et al.,  in preparation, 2016
Using New Quasi in-Situ TEM Technique to Study Structural Changes of Electrode Materials for Li-Ion and Na-Ion Batteries
Authors: Lin Ruoqian , Hu Enyuan , Yu Xiqian , Yang Xiao-Qing , Xin Huolin L.
Published: February 2020

In this poster, we report the development of a quasi in-situ TEM technique to study structural changes of electrode materials for Li-ion and Na-ion batteries. Some preliminary results about structural (ir)reversibility of NiO conversion anode materials relating to the materials’ size and morphology will be discussed as an example. Using a quasi in-situ TEM setup, we were able to track the structural changes of electrode materials in marked locations on a TEM grid repeatedly before and after electrochemical lithiation/delithiation in LiPF6/EC/DEC electrolyte. This method is a further development of the TEM grid-in-a-coin cell method reported in the literature (F Lin et al, Nat. Comms.,5, 3356 (2014)) with much improved capability to locate the same materials on the TEM grid before and after charging/discharging. Our results show that upon lithiation, NiO is converted into a three-dimensional nanoporous network of metallic Ni. However, we found that the structural reversibility of NiO upon delithiation is highly dependent on the initial size and morphology of the materials. Particularly in our 10 nm-thick NiO nanoplate materials, the nanoporous structure can be removed and the solid-form palette structure can be fully recovered when the material is delithiated. This study shows that that size effect can be an important parameter in dictating the structural reversibility of transition metal oxide conversion 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 under Contract Number DE-SC0012704. 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.
Fluoride-Phosphate Cathode Materials for Li-Ion Batteries: The Impact of Structure on Electrochemical Activity
Authors: Khasanova Nellie R. , Fedotov Stanislav S. , Manoilov Alexej I. , Samarin Aleksandr Sh. , Karakulina Olesia M. , Abakumov Artem M. , Antipov Evgeny V.
Published: February 2020

Today researches in the field of cathode materials for Li-ion batteries are directed towards the development of new materials with high power and energy densities, especially to answer the requirements of large scale applications. In this respect, fluoride-phosphate materials are very attractive as they demonstrate wide structural diversity. Furthermore, they are expected to exploit the advantages of both anion species: the increase in the working potential due to inductive effect of the polyanion group and higher ionicity of the M−F bond, faster kinetics arising from lower affinity of lithium to the F-anion.1

In the search for new cathode materials for Li-ion batteries we have explored the A2MPO4F and AMPO4F (A=Li, Na, K, and M=Co, Mn, Fe, V) fluorophosphates families. The fluoride-phosphate phases were prepared through different synthetic routes depending on the chemistry of transition metal. Combination of X-ray/neutron diffraction and electron microscopy were applied for a thorough structural characterization. It was shown that in these systems the substitution on the alkali metal site leads to the wide range of adopted structures. Thus, in the Li2FePO4F system synthesis of sodium-containing counterpart, NaLiFePO4F, followed by subsequent electrochemical exchange of Na by Li leads to the cathode material with a 3D “stacked” structure.2 In the (Li,Na)2CoPO4F system it provides a new low-temperature polymorph adopting a complex layered structure, in contrast to the high-temperature phase with 3D “stacked” arrangement. The introduction of large potassium into the AMPO4F system gives a raise to a new cathode material with a KTP structure, which exhibits excellent rate capability.3 Reversible electrochemical activity demonstrated by these fluoride-phosphate materials in Li-cell will be discussed. A special attention will be given to the structure peculiarities and their impact on electrochemical properties, which is important for possible practical applications of these materials.

The work was partly supported by Russian Science Foundation (grant 16-19-00190), Skoltech Center for Electrochemical Energy Storage and Moscow State University Development Program up to 2020.

References

Antipov, E. V.; Khasanova, N. R.; Fedotov, S. S. International Union of Crystallography Journal 2015, 2, 85-94

Khasanova N. R., Drozhzhin O. A., Storozhilova D. A., Delmas C., Antipov E. V. Chem. Mater., 2012, 24, 4271–4273

Fedotov, S. S.; Khasanova, N. R.; Samarin, A. Sh.; Drozhzhin, O. A.; Batuk, D.; Karakulina, O. M.; Hadermann, J.; Abakumov, A. M; Antipov, E. V. Chem. Mater. 2016, DOI: 10.1021/acs.chemmater.5b04065
Unexpected Dilation and Dilation Relaxation Behavior of Graphite-Based Lithium-Ion Cells
Authors: Bauer Marius , Wachtler Mario , Persson Jon V. , Danzer Michael A.
Published: February 2020

The dilation of lithium-ion cells is sensitive to swelling phenomena caused by both graphite staging processes and lithium plating on graphite anodes. In this work, the dilation behavior of graphite/NMC pouch cells is studied with a focus on relaxation phenomena occurring after current pulses.

Dilation data are recorded for quasi-equilibrium cycling as well as for current pulses at high rates. In the quasi-equilibrium case, the staging behavior is characterized based on dilation and voltage data. By comparison with a graphite half-cell measurement, the major effects in full cell dilation are confirmed to be anode-related. In the high rate case, the dilation responses to the actual pulse and the subsequent relaxation phases are recorded systematically for different SOCs and temperatures. Positive and negative relaxation phenomena are observed as exemplified in Fig. 1. They are ascribed to both graphite staging and lithium plating processes. A model is introduced explaining the unexpected relaxation effects in all SOC ranges by a temporary coexistence of three or more staging compounds during high-rate lithiation/delithiation. These data thereby confirm the shrinking annuli model recently introduced by Heß and Novák [1].

Additionally, the effects of thermal expansion on dilation data recorded on pouch cells are investigated. In order to prevent misleading interpretations due to thermal effects, thermal expansion is quantified and a method for the thermal compensation of dilation data is developed. It is shown that for measurements at constant ambient temperature, the bias from thermal expansion is small compared to the other dilation effects. With regard to the application of dilatometry at varying temperatures, however, it is crucial to compensate for thermal expansion in the measurement data.

Based on the findings presented in this work, dilation relaxation can be used as an indicator for kinetic limitations leading to deviations from the low-rate staging course during graphite lithiation. The results provide a basis for the development of a new dilation based approach to lithium plating prevention.

Acknowledgements

This research project is supported by the Federal Ministry for Economic Affairs and Energy (BMWi) under contract number 03ET4012C. All responsibilities for this publication rest with the authors.

Figure Caption

Figure 1: Relaxation of cell thickness after current pulses at I=1C from SOC=0% to SOC=25% for different temperatures.

References

[1] Heß, M., & Novák, P. (2013). Shrinking annuli mechanism and stage-dependent rate capability of thin-layer graphite electrodes for lithium-ion batteries. Electrochimica Acta, 106, 149–158. doi:10.1016/j.electacta.2013.05.056

Figure 1
Electrospun Membranes Based on PVdF-PEO Blends for Lithium Batteries
Authors: La Monaca Andrea , Arbizzani Catia , De Giorgio Francesca , Focarete Maria Letizia , Fabiani Davide , Zaccaria Marco
Published: February 2020

Solid polymer electrolytes (SPEs) in lithium batteries have the dual function of electrolyte and separator to hinder lithium dendrite growth that causes hazardous short circuits during repeated charge/discharge cycles [1]. Polyethylene oxide (PEO), together with a lithium salt, would be a promising candidate as SPE for its good electrochemical and mechanical properties, but its low ionic conductivity at room temperature limits its use. In the last years the attention has been focused on gel polymer electrolytes (GPEs) for the high ionic conductivity at room temperature, good mechanical properties and safety improvements [2]. GPEs can consist of a flexible polymeric matrix as supporting network and a liquid phase containing a lithium salt [3]. Several polymers, like polyvinylidene difluoride (PVdF) for the high dielectric constant and the good electrochemical stability, and PEO have been used as matrix for GPEs.

Given the good compatibility between PVdF and PEO and with the aim to merge the properties of these two polymers, we prepared and characterized PVdF/PEO membranes that act as separators and as hybrid gel polymer electrolytes (HGPEs) when soaked in the liquid solvent with lithium salt. The membranes based on the polymer blends were prepared by electrospinning, a technique that yields micro-nanofibrous membranes with high porosity and, hence, huge values of electrolyte uptake [4]. PEO 100,000 and PEO 1,000,000 were used to prepare two blends with PVdF:PEO 90:10 w/w composition. Such membranes were soaked in 1M LiPF6 – ethylene carbonate:dimethyl carbonate (1:1 w/w) and the electrochemical performance of these HGPEs were tested in a Li/HPGE/LiFePO4 cell and discussed on the basis of their physical, mechanical, thermal and morphological properties.

Acknowledgments

Alma Mater Studiorum –Università di Bologna is acknowledged for RFO financial support

References

[1] Croce, F.; Focarete, M. L.; Hassoun, J.; Meschini, I.; Scrosati, B. Energy Environ. Sci.
2011, 4, 921-927

[2] Manuel Stephan, A. European Power Journal
2006, 42, 22.

[3] Marcinek, M.; Syzdek, J.; Marczewski, M.; Piszcz, M.; Niedzicki, L.; Kalita, M.; Plewa-Marczewska, A.; Bitner, A.; Wieczorek, P.; et al. Solid State Ionics
2015, 276, 115.

[4] Zaccaria, M.; Fabiani, D.; Cannucciari, G.; Gualandi, C.; Focarete, M. L.; Arbizzani, C.; De Giorgio, F.; Mastragostino, M. J. Electrochem. Soc.
2015, 162, A915.
Development of Sulfolane-Based Electrolytes for Li-ion batteries
Authors: Zhang Tong , Porcher Willy , Paillard Elie
Published: February 2020

The quest for higher energy density Li-ion batteries pushes toward ‘high voltage’ cathode operating above 4.5V. However, if such materials have been proposed for many years in the case of LiNi0.5 Mn1.5 O4
1 or more recently for LiCoPO4F2, the implementation of such materials is currently prevented by the lack of adapted electrolyte. Several reports deal with high voltage electrolytes such as ionic liquids, dinitrile compounds or fluorinated carbonates. Yet, another class of solvents investigated are the alkyl sulfone, linear3 or cyclic4. Among them, sulfolane, despites its high viscosity has been reported to allow low potential anode operation (such as Li metal or graphite), while other reports point out the high oxidative stability of the electrolytes made thereof4, which was explained based on fundamental studies such as QC5 and MD6. Mixtures of sulfolane seem able to allow room temperature operation of both graphite and high voltage electrodes but no report can be found of a sulfolane-based electrolyte compatible, at the same time, with graphite and a high voltage electrodes. Thus, we examine here the possibility of forming new electrolyte system, based on sulfolane/DMC mixtures for room temperature operation. In particular, the role of the Li salt has been investigated as it is known to play a role on conductivity, via viscosity and dissociation in a solvent system that has a lower dielectric constant and higher viscosity than alkyl carbonate mixtures such as EC/DMC. In addition, keeping the application in mind, SEI building on graphite and aluminum current collector corrosion are also dependent on the Li salt or mixture used. Thus several inorganic and organic Li salts have been investigated in terms of conductivity and electrochemical stability and tested versus graphite and LiNi0.5 Mn1.5 O4 electrodes in a DMC/sulfolane mixed solvent.

References

1. Q. Zhong, A. Bonakclarpour, M. Zhang, Y. Gao, and J. R. Dahn, J Electrochem Soc, 144, 205–213 (1997).

2. S. Okada, M. Ueno, Y. Uebou, and J. I. Yamaki, J. Power Sources, 146, 565–569 (2005).

3. C. A. Xu, K. Angell, J. Electrochem. Soc., 145, L70 (1998).

4. A. Abouimrane, I. Belharouak, and K. Amine, Electrochem. commun., 11, 1073–1076 (2009)

5. O. Borodin, W. Behl, and T. R. Jow, J. Phys. Chem. C, 117, 8661–8682 (2013).

6. L. Xing, J. Vatamanu, O. Borodin, G. D. Smith, and D. Bedrov, J. Phys. Chem. C, 116, 23871–23881 (2012)

The research presented is part of the ‘SPICY’ project, funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 653373.
Design on CFx Cathode for Sodium Secondary Batteries
Authors: Liu Wen , Shadike Zulipiya , Li Yong , Fu Zhengwen , Xie Jingying
Published: February 2020

After investigations on many kinds of fluorides, carbon fluoride (or graphite fluoride, CFx) is the best material as cathode of primary lithium battery with ultrahigh energy density [1-2], while F2 gas is difficult to operate as cathode. And many attempts for extending the application concepts of CFx in lithium batteries were made to conclude no any evidence on its reversibility[3]. Since sodium batteries have been attracting much attention as one of the post-lithium ion battery[4]. CFx/Na cells were explored and the reversibility of these cells was also proved[5-6].

Here, we summarize these designed CFx materials for sodium secondary batteries, as shown in Figure 1. Commercial CFx and F-MWCNTs were synthesized by direct fluorination of graphite and mutil-wall carbon nanotubes (MWCNTs) using F2 gas. While CGF powders were prepared by simply ball-milling of the commercial CFx, FeF3 and GNS, with higher surface area, electronic conductivity, more active sites and specific channels for the transportation and storage of fluorine ions. Furthermore, disordered CFx exhibits excellent electrochemical performance due to its intrinsic amorphous character.

Figure 1 Three kinds of CFx materials for sodium secondary batteries:(a) commercialCFx, (b) CFx/GNS/FeF3(CGF) composite, (c) F-MWCNTs

Commercial CFx was first used in sodium secondary battery[5]; however, much larger overpotential(2000mV) between charge and discharge voltage and terrible cyclic performance (5 cycles) hindered its practice adoption. These drawbacks can be overcome by the introduce of catalysts and the change of the intrinsic characteristic of CFx materials[5-6], which results in a gap of only 0.8 volt and enhanced cycle life.

For practical uses, some popular approaches in nanotechnology and electrolyte chemistry such as the core-shell structure or encapsulation or coating composites, and using specially designed solid electrolytes will be expected to prevent the dissolution of fluorine for improving cycle life for Na-CFxbattery in the future.

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (NSFC21373137) and Shanghai Science and Technology Development Fund (15DZ2282000).

Reference

[1] N. Watanabe, M. Fukuda, U.S. Patent 3 536 532, 1970 and 3 700502, 1972.

[2]  M. Fukuda, Iijima, T. In Collins, D.H., Ed.; Power Sources 5;Academic Press: New York, 1975; p 713.

[3] G. G. Amatucci, N. J.  Pereira, Fluorine Chem. 2007, 128, 243.

[4] D. S. Michael, K. Donghan,L.  Eungje, and S. J. Christopher, Sodium-Ion Batteries, Adv. Funct. Mater. 2013, 23, 947.

[5]   W. Liu, H. Li, J. Y.Xie, and Z. -W. Fu, ACS Appl. Mater. Interfaces, 2014, 6, 2209.

[6]   W. Liu, Z. Shadike, Z. C. Liu, W. Y. Liu, J. Y.Xieand Z. -W. Fu, Carbon, 2015, 523.

[7]   Y. Shao, H. Yue, Z. Gong and Y. Yang, The 18th National Conference on Electrochemistry. August, 2015, Haerbin, China.

Figure 1
Enhanced Electrochemical Performance of Bismuth Oxide/Phosphorus Nano Composites Anode for Sodium Ion Battery
Authors: Jin Aihua , Yu Seung-Ho , Mun Junyoung , Sung Yung-Eun
Published: February 2020

The electrochemical energy conversion and storage devices have to be large to go through a new paradigm in which the huge power sources are required to handle kWh or MWh energies for highly efficient energy storage system and electric vehicles. Despite lithium ion batteries (LIBs) have been widely applied as major power sources for small portable electronic devices during several decades, they will no longer be so easy to use owing to high cost and limitation of lithium resources. Nowadays, sodium ion batteries (NIBs) have attracted increasing attention as alternative power sources to LIBs due to the abundant supply and low cost. In this regard, a lot of researchers have vigorously investigated the active materials for cathode and anode to utilize sodium ion battery. Additionally, developing new electrode materials with high specific capacity for excellent sodium ion storage properties is very desirable for high energy power sources. As an anode material, red phosphorus is very promising thanks to its high theoretical capacity (∼2600 mA h g-1), however, it has several problematic issues of undesirable low cycle life from the large volume change during sodiation/desodiation and insufficient power density from the poor conductivity. We add Bi2O3 to phosphorous for reducing those failure modes of phosphorus for NIBs because Bi2O3 has high electronic conductivity and small volume changes during cycles. In this presentation, we tried to improve the electrochemical performances of phosphorus by introducing the composite material of bismuth oxide (Bi2O3)/phosphorus by controlling the nano-morphology via simple top down method of ball milling. The prepared sample was investigated by using XRD, SEM and TEM analyses to follow the sample morphology for anode of NIBs. It is found that the addition of Bi2O3 has an effect on relieving volume expansion during cycling, and consequently they showed specific capacity of ca. 400 mA h g-1 after 30 cycles when the ratio of bismuth oxide/phosphorus is 3:1. It is profoundly investigated that the mechanism for the electrochemical improvement of the NIBs by using systematic analyses tools of electrochemical and instrumental analyses of XRD, SEM and TEM.
Na2RuO3: A Model to Study the Extra Capacity of a
2
mO3 Type Cathodes
Authors: Mortemard de Boisse Benoit , Liu Guandong , Ma Jiangtao , Nishimura Shinichi , Chung Sai-Cheong , Kiuchi Hisao , Harada Yoshihisa , Kikkawa Jun , Yoshio Kobayashi , Okubo Masashi , Yamada Atsuo
Published: February 2020

Li-ion batteries power almost all of today’s portable electronics as well as electric and hybrid vehicles thanks to their important energy density. However their high cost tend to prevent larger-scale application such as in power grids. On the other hand, Na is abundant, easily accessible and therefore cheaper than Li. As a consequence, Na-ion batteries draw a lot of attention since the 2000s.

Even though Nax
MO2 (x ≤ 1, M = transition metal) materials have been studied for a long time as positive electrode candidates, the available capacity is still limited. Partial substitution of M by Na+ is an appealing strategy to overcome this issue: the excess Na+ ions in the MO2 layer could participate in the (de)intercalation process while lowering the weight of the battery, thus greatly enhancing the gravimetric capacity. This strategy, applied to Li-ion batteries for many years, is still poorly transferred to Na-ion battery materials.

In order to establish a model for the study of Na2
MO3 – and A2
MO3 in general –, we prepared two polymorphs of O3-Na2RuO3 distinguished by the honeycomb-like ordering of the [Ru2/3Na1/3]O2 layers [1,2]. In both samples, we found that Na in the interlayer and in the [Ru2/3Na1/3]O2 layers is accessible. In ordered-Na2RuO3, the honeycomb ordering triggers the spontaneous formation of an ilmenite-type intermediate which facilitates highly reversible oxygen redox chemistry, associated to a large extra capacity (Figure 1) as well as noticeable structural stability upon cycling making it, to our knowledge, the first Ax
MO3 to do so.

Figure 1. Galvanostatic cycling curves for (a) disordered and (b) ordered O3-Na2RuO3 (first cycle highlighted in blue). The insets represent the coordination environment of Na at x = 1.

Figure 1
Chemical Intercalation and De-Intercalation Studies on Multivalent Ion Cathodes
Authors: Senguttuvan Premkumar , Burrell Anthony K. , Johnson Christopher
Published: February 2020

As the lithium ion battery technology matures, it becomes apparent that the energy density is more limited by the materials used.  Beyond-Li ion battery technology is now garnering more interest, and, as such, the search for new greater energy storage materials is underway.  For us we are pursuing multivalent batteries [1] and are investigating new cathode materials, in hopes of discovering and designing new (de)intercalation hosts, or possibly cathodes that hold multivalent cations (Mg2+, Zn2+, Ca2+) by other storage mechanisms as well at high voltages.  In particular, oxide cathodes, for example bilayer-V2O5 (BL-V2O5) [2]or alpha-MnO2(hollandite, 2x2 tunnel structure) [3], have been explored for high voltage intercalation. Unfortunately many problems abound, such as poor diffusion of multivalent cations due to strong electrostatic interactions with the oxide lattice.

The development of multivalent ion electrolytes is also at its infancy and it is required to exhibit high voltage stability, compatibility with cathode and inactivity towards cell components.  Viable electrolytes for this battery task are hard to find, and thus limit our productivity.  Nevertheless, the search and evaluation and synthesis will require the means to
chemically cycle
the materials. A few reagents like di-n-butyl magnesium, di-ethyl zinc have been reported to intercalate Mg2+ and Zn2+ions [4],[5]. In this work and poster, we will discuss and demonstrate a new method of utilizing novel reagents to intercalate multivalent cations into a variety of host materials.

References

[1]        J. Muldoon et al., Chem. Rev. 114 (2014) 11683–11720.

[2]        S. Tepavcevic et al., ACS Nano. 9 (2015) 8194–8205.

[3]        R. Zhang et al., Electrochem. Commun. 23 (2012) 110–113.

[4]        P.G. Bruce et al., Solid State Ionics 53–56, Part 1 (1992) 351–355.

[5]        H. Wang et al., ECS Electrochem. Lett. 4 (2015) A90–A93.

Acknowledgments

 This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U. S. Department of Energy, Office of Science, Basic Energy Sciences. Work done at Argonne and use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory, were supported by the U.S. Department of Energy under Contract No. DE-AC02-06CH11357.
Cathode to Cathode Lithium Ion Battery Recycling
Authors: Wang Yan , Gratz Eric , Heelan Joseph , Zheng Zhangfeng
Published: February 2020

Due to their high energy density, long lifespan and light weight, lithium ion (Li-ion) batteries accounted for $11.8 billion dollars in sales in 2012, that makes up 60% of total portable battery sales and 37% of total battery sales. The same factors also make them the best candidate for use in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Currently in the US almost all spent lithium ion batteries are land filled, compared to other types of batteries, such as lead acid batteries, in which 97% are recycled.  This presents a large amount of environmental waste.  Based on current trends in Li-ion battery use, if Li-ion batteries are not recycled, global lithium reserves are expected to be depleted by 2050.  Additionally, recycling Li-ion batteries presents an economic opportunity in through the recovery of key valuable metals, such as cobalt, nickel and copper. Currently, most Li-ion battery recyclers focus on recovering cobalt from LiCoO2 cathode material or through the recovery of Co and Ni from the cathode materials via a high temperature pyrometallurgical approach. We propose a new methodology that uses a low temperature hydrometallurgical approach that has the advantage of having high efficiency of recovery. This process works regardless of the Li-ion batteries chemistry, shape and size and recovers Co, Ni, and Mn in the form of their hydroxides, which when sintered with recovered Li2CO3 produces new LiNixMnyCozO2 cathode materials.  The regenerated cathode material, LiNixMnyCozO2 , has been tested and exhibits good electrochemical performance. In addition to the cathode material, copper, aluminium, steel, etc are also recycled.

Figure 1
Using XPS to Determine the Relative Thickness of Lithium-Ion Surface Films at the Negative Electrode
Authors: Somerville Limhi , Bareno Javier , Prezas Panos D. , Basco John K. , Jennings Paul , McGordon Andrew , Lyness Christopher , Duong Tien Q. , Bloom Ira
Published: February 2020

During typical lithium-ion cell usage over application lifetimes (e.g. automotive) they form a film, which is nanometres thick, on the surface of the negative electrode which helps to passivate against further reaction. Its chemical composition and thickness affect capacity and power capabilities of a cell through 1. Consumption of lithium inventory during the surface film forming reactions and 2. More surface film which increases surface resistance. Over time and with further cycling, this film thickens. Understanding and controlling surface film thickness and composition as well as its relationship to cell operating conditions could provide a pathway to extend cell and device service life.

As a first step toward achieving this goal we focused on characterising surface film thickness as a function of cell age and operating conditions. Currently, there is no reliable method for determining surface film thickness at the electrode surface. We tested the capacity and power of commercial 18650-sized cells cycled at different C-rates or stored at different temperatures and states of charge. We then present a method of XPS analysis to determine the relative surface film thicknesses within each of these three conditions. XPS analysis was completed at two different institutions on two different systems to determine reproducibility.

The novel XPS method reliably showed that the surface film thickness increased with temperature, state of charge and higher C-rates.

We found that the chemical composition of the surface film changed as a consequence of temperature, State of charge and charge rate. We also found that the thickness of the surface film followed traditional 1-dimensional models of surface film growth, that is, a sharp initial growth followed by a reduced rate after ‘X’ months / C-rate.

These findings indicate that, using our method, it is possible to determine the relative thickness of the negative electrode surface film. It also showed that surface film thickness increased with cell charge- rate, temperature and SoC. This is invaluable in determining the relationship between cell conditions and its effect on internal chemical composition of the cell.

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 issue has been created by the University of Chicago as Operator of Argonne National Laboratory (“Argonne”) under Contract No. W-31-109-Eng-38 with the U.S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, non-exclusive, 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.
High-Performance Germanium Microstructure-Based Li-Ion Battery Anodes Prepared By the Electrochemical Liquid-Liquid-Solid Process
Authors: Ma Luyao , Fahrenkrug Eli , Gerber Eric , Venable Frances , Crowe Adam , Bartlett Bart M. , Maldonado Stephen
Published: February 2020

Microstructured Ge grown by the electrochemical liquid-liquid-solid (ec-LLS) process at < 100 °C demonstrated high specific capacity, excellent capacity retention and rate capabilities. The Ge microwires were first prepared on Su-8 patterned Cu plate in an aqueous solution through ec-LLS at 90 °C. Ge microstructure-based anodes were synthesized through acid etching of Ge microwires. The Ge anode demonstrated specific capacity of 1114 mAh/g at 1st cycle and retained 94% of the capacity after 25 cycles at 0.2 C. Ge microstructure-based anode was cycled at a series of charge/discharge rates and performed well up to 1 C. Ec-LLS grown microstructured Ge can be assembled into button cells for Li-ion battery application without any binder or additive, and this method is highly scalable for different battery prototypes. Microstructured Ge exhibited excellent capacity retention due to both its ability to accommodate volume expansion and mild solid-electrolyte interface (SEI) layer formation. The specific capacities of Ge anode can be plotted as a function of different cycle rates, and the result indicates that the charge/discharge process is limited by solid-state diffusion of Li in Ge.
Activated Lignin Based Carbon Nanofibers As Binder-Free Anodes for Lithium Ion Batteries
Authors: Stojanovska Elena , Serife Pampal Esra , Kilic Ali
Published: February 2020

Anode, as a constituent element of a battery is the crucial component for battery’s cycle life and rate capability. Anodes with different zero-, 1D-, 2D- and 3D nanostructures made of different materials have been proposed. Among them 1D carbon nanofibers (CNF) can provide shorter lithium ion diffusion lengths, electron transport and enhanced surface area. The possibility for adding different active materials into their structure and their usage as free standing electrodes are another advantages of CNF. Another approach to improve battery performances increasing their surface area by activating the carbonaceous material.

Lignin is abundant low-cost polymer obtained from a variety of biomasses by solvent extraction as most common method. As a byproduct of paper industry it can be used as fuel additive, emulsifier or dispersant in agriculture, as binder or reinforcement in different composite structures, as antioxidant for polymers. Due to its highly functionalized macromolecules can be used as starting material for renewable polymers, such as polyesters, polyurethanes or polyanilines. Besides, its high carbon content allows its usage as precursor polymer for carbon production. As non-toxic and biocompatible polymer is promising precursor to replace PAN in carbon fiber production. However, its low molecular weight is an obstacle for its conversion into nanofiber. One approach to overcome this problem is blending it with high molecular weight polymers, such as poly (vinyl alcohol), polyethylene oxide, poly acrylonitrile, polyethylene glycol, polypropylene, etc.

In this study, lignin/PVA blends were converted into nanofibers by electrospinning. The fibrous structure was further stabilized under iodine vapor and then carbonized in inert atmosphere. Activation of the carbonaceous structure was realized by dissolving the polymers into basic aqueous solution and completed by neutralization with acidic aqueous solution. In order to study the effect of the degree of activation on electrochemical properties, solutions with different KOH concentrations were prepared. As prepared carbon nanofibers were used as free-standing anodes without addition of current collector in a half cell button type Li-ion battery. The change in morphology of the fibers was characterized by SEM, while the change in their chemical structure by RAMAN spectroscopy. Battery rate capability and cycling stability were analyzed by galvanostatic cycling test. The results showed activated lignin-based carbon nanofibers can improve the cycling stability and rate capability when used as anodes in Li-ion batteries.
Atom Probe Tomography Study on Lithiation Behavior in Silicon Alloy Electrodes
Authors: Zheng Yueming , Pradeep Konda Gokuldoss , Renner Frank Uwe
Published: February 2020

With respect to its high specific capacity, silicon would be an ideal replacement for carbonaceous anodes in lithium-ion batteries. But the usage of silicon-based active materials has been hindered by its tremendous volume change and related problems during lithiation cycles. To mitigate the problems, the silicon particles are often used as (expensive) nanoparticles, or some recent strategies include confined Si precipitates embedded in a matrix material. Among others, for example, Si/Ti4Ni4Si7 (STN) has been recently proposed [1]. However, the lithiation mechanisms remain poorly understood for either pure silicon or silicon alloys, due to the silicon (and silicon alloy) amorphization induced by lithiation. We consider Atom Probe Tomography (APT) as a powerful tool [2] to understand the mechanisms of lithium insertion and interaction in silicon alloy electrodes. APT is enabling for a sub-micron sample prepared by Focused Ion Beam (FIB) to address the elemental distribution at the atomic level.  Our results propose a strong contribution of interfaces in such nano-scale Si alloys [3]. In the discharged state we revealed a core-shell structure with the formation of a Li-rich shell surrounding a pure silicon core.  Hereby, not only an accurate composition of this shell is determined by APT, but also the lithium atom position in the matrix is provided.  We believe that this study will be beneficial not only for silicon alloys, but also for understanding pure silicon lithiation mechanisms.

[1] Son  et al. “A Highly Reversible Nano-Si Anode Enabled by Mechanical Confinement in an Electrochemically Activated LiXTi4Ni4Si7 Matrix.” Advanced Energy Materials 2 (2012), 1226.

[2] Diercks et al., Microscopy of Chemical and Mechanical Heterogeneities in Lithium Cobalt Oxide, Microscopy and Microanalysis 21 (2015), 523.

[3] Y.Zheng, KG. Pradeep, F.U. Renner et al., to be published.

Figure 1. The atom probe tomography reconstruction of Silicon atoms in pristine Si/Si7Ti4Ni4.

Figure 1
High-Capacity Li[Ni1-XCox/2Mnx/2]O2 (x = 0.1, 0.05, 0) Synthesized By Co-Precipitation for Next Generation Li-Ion Battery Cathodes
Authors: Lim Byung-Beom , Yoon Chong seung , Sun Yang-Kook
Published: February 2020

LiNiO2 with theoretical capacity of 275 mAh g−1 is regarded as a promising cathode material for Li-ion batteries, but its potential capacity has not been fully realized due to the severe capacity loss in the first charge/discharge cycle. Via co-precipitation method, we synthesized Li[Ni0.90Co0.05Mn0.05]O2, Li[Ni0.95Co0.025Mn0.025]O2, and LiNiO2 which delivered 221, 230, and 240 mAh g−1, respectively, when cycled from 2.7 to 4.3 V vs. Li0/Li+ at 0.1 C and retained ∼70% of the initial capacity after 100 cycles. To date, such high reversible capacities are not yet to be reported from the Ni-rich Li[Ni1−x−yCoxMny]O2 cathodes. The observed high capacities were attributed to the presence of a rock salt phase from severe cation mixing and excess Li ions in the host structure. It is believed that the rock salt phase stabilized the host structure in the delithiated state while the excess Li allowed the Li ions percolated through the rock salt phase which would be electrochemically inactive otherwise.