bluuebunny/crossref_metadata_2025 huggingface dataset:
Passivation Layer of Magnesium-Based Negative Electrodes
Authors: Matsui Masaki , Kuwata Hiroko , Yamauchi Masatsugu , Imanishi Nobuyuki
Published: February 2020

Rechargeable magnesium batteries are getting more interests as a potential beyond Li-ion chemistry in the battery field. Of course a lot of the challenges of the rechargeable magnesium batteries are remaining for cathodes, anodes and electrolytes. In the case of the anode active materials, since formation of the passivation layer at the surface of the magnesium metal is the most critical problem for the reversible deposition and dissolution process, halide based electroltye solutions are preferred. On the other hand, the halide-based electrolyte sotluion always has voltage limitation due to the corrosion of the current collector. As a consequence, it is very challenging to develop a high voltage magnesium batteries.

Previously we reported that the magnesium metal can be easily passivated in the Mg(TFSA)2 BuMe-triglyme solution using XPS and in situ FTIR. It is mainly due to the electrochemical reduction of the TFSA anion to form the passivation layer resulting in the high overpotential. However, a magnesium-based intermetallic compound: Mg3Bi2 showed good reversibility in the Mg(TFSA)2 BuMe-tryglyme solution with very low overpotential. Even though the decomposition of the TFSA anion itself was still observed by XPS, the surface layer formed on the Mg3Bi2 could not be enough stable to work as the passivation layer.

In the present study, we synthesized various magnesium-based intermetallic compounds such as Mg3Bi2, Ma3Sb2 and Mg2Sn via solid-state process and investigated the stability of the passivation layer formed at the surface of the intermetallic compounds. In the ambient atmosphere, Mg3Bi2 and Mg2Sn were easily decomposed to form Bi and Sn respectively. On the other hand, the Mg3Sb2 was extremely stable even with water. These results well matches with the electrochemical performances of the each intermetallic compounds. The obtaind results suggest that the formation of the alloy or intermetallic compounds de-stabilizes the surface of the magnesium. We think the destabilization of the magnesium improves the performance of the anode active materials.
Intermetallic Li-Anode Alloys Based on Cu, Sb and Sn
Authors: Beutl Alexander , Fuertauer Siegfried , Berger Patric , Li Dajian , Cupid Damian Marlon , Flandorfer Hans
Published: February 2020

Intermetallic alloys are promising candidates for new anode materials for lithium ion batteries (LIBs) in high energy applications because of the significantly increased theoretic capacities when compared to conventionally used graphite. However, the drastic volume changes during lithiation of pure metals such as Si or Sn lead to degradation of the electrode material resulting in very high capacity fading and low cycling stability. One of the various concepts to solve this problem is to use intermetallic alloys instead of pure metals. For example, Cu6Sn5, Cu3Sn and Cu2Sb are promising anode materials because Cu does not form intermetallic compounds with Li. A (Cu)-alloy matrix which precipitates during lithiation would act to buffer the strain induced by volume changes and simultaneously ensures electrical contact between lithiated phases. A similar effect can be observed using SbSn as anode material. In this case Sn acts as a buffer because Li-Sb alloys are preferably formed by lithiation.

Advanced materials design and engineering based on computational methods rely significantly on experimentally determined thermodynamic and phase diagram data of the material systems. These data are used as inputs to model the Gibbs free energies of all phases, thereby generating self-consistent thermodynamic descriptions of the multi-component systems. These can in turn be used to predict lithiation pathways and simulate the electrochemical behaviour of half cells with different active material compositions. Furthermore, knowledge of phases and their crystal structures is crucial for kinetic studies of lithiation processes. From our comprehensive experimental data, including powder X-ray diffraction, single crystal X-ray diffraction, thermal analysis, and coulometric titration, we obtained self-consistent CALPHAD descriptions.This presentation will give an overview of our experimental procedures and the results of our work on the materials systems Cu-Li-Sn, Cu-Li-Sb and Li-Sb-Sn.

This work has been funded by the FWF under the project I559-N19 and by the DFG under the projects FL-730/1-2 and CU 203/ 1-2, all within the DFG priority project SPP 1473 “WeNDeLIB”.
New Intermetallic Anode Materials for Lithium Ion Batteries: Experimental Investigation of the Cu-Li-Sn System
Authors: Fuertauer Siegfried , Flandorfer Hans
Published: February 2020

Intermetallic anodes are promising candidates of new anode materials for lithium ion batteries. Therefore the knowledge of relevant alloy phase diagrams containing lithium is mandatory to understand the nature and mechanisms of charging and discharging intermetallic anodes, like e.g. Cu-Sn alloys. The Cu-Li-Sn phase diagram and the constituting binary systems Cu-Sn, Li-Sn and Cu-Li have been investigated extensively by experimental methods. Powder-XRD, SC-XRD studies and thermal analysis were applied to describe the alloy phase diagrams. Drop calorimetry was performed to provide supplementary data for the thermodynamic optimization. Based on the phase diagram a lithiation route for Cu-Sn alloys was suggested. The outcome of this work is fundamental for further application-oriented studies, e.g. the calculation of the open circuit voltage. This work has been funded by the FWF under the project I559-N19 within the DFG priority project SPP 1473 “WeNDeLIB”.
Specific Capacity and Capacity Fading of Interstitial and Substitutional Doping of Li in LiNi0.6Co0.3Ti0.1O2 Nano Cathode Material for High Energy Density Li-Ion Battery
Authors: Kamarulzaman Norlida , Rusdi Roshidah
Published: February 2020

Pure and single phase LiNi0.6Co0.3Ti0.1O2, Li1.05Ni0.6Co0.3Ti0.1O2, Li1.05Ni0.55Co0.3Ti0.1O2 materials were successfully prepared using a self-propagating combustion method. The structure and morphology of the materials were characterized using X-Ray Diiffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray Spectroscopy (EDX). The oxidation state of elements and their chemical environments were studied using X-Ray Photoelectron Spectroscopy (XPS). The electrochemical performances of the materials were carried by means of galvanostatic charge-discharge on the fabricated cells. XRD results showed that the materials are impurity-free and single phase with well ordered hexagonal layered structure of R-3m space group. The discharge capacities are between 141 and 145 mAhg-1. The interstitially doped Li1.05Ni0.6Co0.3Ti0.1O2 compound exhibits the highest first cycle capacity of 145.3 mAhg-1 over the voltage range of 2.5 to 4.2 V compared to the undoped sample, LiNi0.6Co0.3Ti0.1O2, showing a capacity of 105.5 mAhg-1. The 70th cycle revealed that the Li interstitially doped material (Li1.05Ni0.6Co0.3Ti0.1O2) shows the highest specific discharge capacity of 132.4 mAhg-1. The capacity fading is only about 8.9% compared to 25.4% for undoped LiNi0.6Co0.3Ti0.1O2 and 10.4% for Li substitutionally doped material (Li1.05Ni0.55Co0.3Ti0.1O2). XPS studies showed that the binding energy of Li 1s is lowest for the best performance compound meaning that the Li+ ions can be extracted more easily from Li1.05Ni0.6Co0.3Ti0.1O2 than the other two materials supporting the electrochemical behaviour of the materials.
Iron Oxide Nanosheets As High Performance Cathodes for Lithium-Ion and Sodium-Ion Batteries
Authors: Niu Sibo , Godinez-Salomon Fernando , Rhodes Christopher
Published: February 2020

Cathodes with high lithium-ion and sodium-ion capacities, the ability to be rapidly charged and discharged, and that are extremely low-cost are needed for numerous applications including electric vehicles, consumer devices, and grid-level energy storage. Iron oxides are of significant interest based on their low cost, low toxicity, and high natural abundance, however iron oxide cathodes typically have low specific capacities and very poor rate capabilities. Our work has shown that synthesizing and stabilizing iron oxide in a nanosheet architecture results in significantly improved lithium-ion charge storage capacities compared to iron oxide nanoparticles at both slow and fast charging/discharging times. The iron oxide nanosheets were determined to have lateral dimensions of ~50 nm, thicknesses of ~1 nm, and be composed of smaller crystallites. From X-ray diffraction, Raman spectroscopy, and high resolution microscopy, the structure of the nanosheets was consistent with maghemite, γ-Fe2O3. The γ-Fe2O3 nanosheets exhibit significantly better electrochemical properties with higher capacities and rate capabilities (110 mAh/g at ~3C) compared with comparable iron oxide nanoparticles. The improved electrochemical performance of γ-Fe2O3 nanosheets has been demonstrated to be related to multiple factors including high surface area, a predominantly surface charge storage process, and higher electronic conductivity. Our recent work has explored using γ-Fe2O3 nanosheets for sodium-ion battery cathodes. The understanding of the unique electrochemical properties, factors that stabilize the nanosheet form, and distinct charge storage mechanism of iron oxide nanosheets furthers the design of improved charge storage materials with improved capacities, rate capabilities, and lower cost.
(Invited) Three-Dimensional Carbon Nanostructures for Advanced Rechargeable Batteries
Authors: Choi Wonbong
Published: February 2020

Next-generation energy storage devices, such as Li-ion batteries (LIBs), demand high energy, power and better safety. Conventional graphite anode falls short of fulfilling all these necessities. Carbon nanostructural materials (graphene and carbon nanotubes) have gained the spotlight as promising anode materials for energy storage; they exhibit unique physico-chemical properties such as large surface area, short Li+ ion diffusion length, and high electrical conductivity, in addition to their long-term stability. Among all published literatures in Li-ion battery, nanostructured carbon materials occupy ~ 70%. Such an impressive figure signifies high interest and promising future of this class of materials in energy storage devices and compels us to look into the involved issues deeply. Carbon-nanostructured materials have issues with low areal and volumetric densities for the practical applications in electric vehicles, portable electronics, and power grid systems, which demand higher energy and power densities. One approach to overcoming these issues is to design and apply a three-dimensional (3D) electrode accommodating a larger loading amount of active anode materials while facilitating Li+ ion diffusion. Furthermore, 3D nanocarbon frameworks can impart a conducting pathway and structural buffer to high-capacity non-carbon nanomaterials, which results in enhanced Li+ ion storage capacity.

In this presentation, the current status of the design and fabrication of 3D carbon nanostructures will be reviewed. Our recent progress on 3D carbon nanomaterials for LIBs and Li-S batteries will be presented. Finally, the performance of 3D carbon nanomaterials based LIBs and Li-S batteries will be presented along with their mechanistic analysis and the perspective of practical applications in devices and systems.

Figure 1
The Direct Forming of Ternary Metal Fluoride Thin Film Electrode By Pulsed Laser Deposition
Authors: Zhao Yu , Liu Xiaojiang , Wei Kaiyuan , Wang Jiali , Chen Hong , Cui Yanhua
Published: February 2020

The rechargeable Li-ion batteries are the preferred the energy storage devices for electric vehicles and portable electronics. The potential probability of leakage and combustion caused by liquid electrolyte is being the current challenge. In recent years, the concept of all-solid-state thin film batteries has been mentioned due to the requirement of safety and flexibility. However, the conventional cathodes with low special capacity (140-170 mAh g-1) limit the improvement when used the next-generation anodes Sn and Si. Specifically, the fluoride-based materials have been the interests once again due to the higher theoretical capacities (3 to 4.2 times to the commercial cathodes).[1] More recently, a new insight into the mechanisms involved in ternary metal fluorides, which is designed the possibility of solid-solution Cu0.5Fe0.5F2 to figure out the poor electronic conductivity, large polarization and cyclic instability in the binary transition-metal fluoride.[2]

In this work, we have been increasingly interested in the direct synthesis of the electro-active Cu0.5Fe0.5F2 thin films electrodes by Pulsed Laser Deposition approaches. Thin film depositions were performed from high purity LiF, Fe and Cu mixed targets (mol ratio 4:1:1) at room temperature. The initial electrochemical oxidation occurs at the first charge to form solid-solution Cu0.5Fe0.5F2 shown in the CV curve. During the delithiation process, the oxidation of Fe (Fe0 to Fe2+) occurs at 3.0 V, and further oxidation to higher valence state at 3.3 V. In the higher voltage region, the oxidation peak at 3.8 V indicated the conversion from Cu0 to Cu2+ and the forming of solid-solution Cu0.5Fe0.5F2. The lithiation process is quite different from the charge process. The CV curve clearly indicated the reduction of Fe and Cu presented overlap range from 3.7 V to 3.2 V, which may promoted the conversion to forma disordered rutile-like Cu–Fe–F phase. The final results may weaken the low hysteresis of Fe and the dissolution of Cu. The novel ternary metal fluoride is appealing for use in all-solid-state thin film Li-ion batteries.

Fig.1 The cyclic voltammetry curve of Cu0.5Fe0.5F2 at scan rate 0.1 mV/s.

Reference

[1] Donato E. Conte, Nicola Pinna, A review on the application of iron(III) fluorides as positive electrodes for secondary cells, Mater Renew Sustain Energy (2014) 3:37.

[2] Feng Wang, Sung-Wook Kim, Jason Graetz, et al. Ternary metal fluorides as high-energy cathodes with low cycling hysteresis, NATURE COMMUNICATIONS (2015) 6:6668.

Figure 1
New Approaches to Raising Redox Shuttle Oxidation Potentials
Authors: Kaur Aman Preet , Odom Susan A , Modekrutti Subrahmanyam , Elliott Corrine F , Risko Chad , Parkin S R , Casselman Matthew D
Published: February 2020

The redox potentials of pi-conjugated organic molecules and polymers are essential factors that determine in part their performance in energy collection and storage applications. In these systems, the control of redox potentials usually involves substitution with electron-donating and/or electron-withdrawing groups, making use of the well-known Hammett constants as predictors of the extent of the change of redox potentials. An additional, less utilized route exploits strain-induced disruptions of π-conjugated frameworks by either (1) introducing bulky substituents to manipulate the dihedral torsions among the π-conjugated moieties or (2) to instill curvature into pi-conjugated networks. In each of these strained examples, the π-conjugated networks are strained in both the ground (neutral) and ionized (oxidized or reduced) electronic states. Taking these studies as inspiration, we sought to develop molecular design principles that impart strain in π-conjugated molecules in only one electronic state, enabling a new method to synthetically control redox potentials. This presentation will include on our approaches to raising oxidation potentials, including calculations, synthesis, electrochemical analysis, and – in some cases – cycling in overcharging lithium-ion batteries. A key highlight is the use of electron-donating alkyl groups to raise oxidation potentials – the opposite effect to what Hammett constants predict.
High Voltage Behavior of Ni-Rich Li(NixMnyCoz)O2 Cathodes in Li-Ion Batteries
Authors: Renfrew Sara E , McCloskey Bryan D
Published: February 2020

Lithium nickel-manganese-cobalt oxide (Li(NixMnyCoz)O2 with x+y+z=1, written as NMC), when used as a cathode in Li-ion batteries, has an achievable capacity of approximately half of its theoretical capacity. The inability to utilize the entire Li content in NMC and achieve the full theoretical capacity is due, in part, to instabilities at high voltage. A higher charge cut-off potential, while increasing achievable capacities, leads to poor long-term cycling performance and a diminished useful battery lifetime. To explore the mechanism of the undesirable decomposition in the overcharged, high voltage limit, we studied the role of Ni content and charge cut-off potential on the efficiency of Li (de)intercalation in NMC oxides by using a combination of in situ differential electrochemical mass spectrometry (DEMS), isotopic labeling, and complementary surface characterization. The results show that gaseous decomposition products are evolved in several distinct regimes, in which the phenomena of Li plating at the Li anode, electrolyte oxidation, and cathode decomposition can be distinguished. Our findings highlight that impurity surface species on the cathode play a significant role in first cycle inefficiency.
A Laminar Graphene As a High Performance Anode Material for Lithium-Ion Batteries
Authors: Ma Kun , Chen Zhongyi , Zhang Yanzong , Liu Yan
Published: February 2020

A novel membrane electrode was fabricated by coating conductive slurry (K/Graphene composites as its important component) on copper foil. The membrane electrode, as anode of lithium ion battery, exhibit excellent coulombic efficiency and specific capacity of 831 mAh g-1 after 1000 cycles. The K/Graphene composites presented a multi-layer nanostructures. It provided not only more intercalation space and intercalation sites for Li+ during the Li+ intercalation/extraction, but also alleviated the agglomeration of dispersed nanocrystals, as well as decreased the electrochemical impedance. The results suggest that them embrane electrode holds great potential as an anode material for LIBs.
Novel Cathode Materials for Na-Ion Batteries Composed of Nano-Rod Primary Particles in Spherical Secondary Particles
Authors: Hwang Jang-Yeon , Myung Seung-Taek , Yoon Chong seung , Kim Sung-Soo , Aurbach Doron , Sun Yang-Kook
Published: February 2020

NIBs have attracted significant interest during the last decade due to their cost-effectiveness compared to LIBs since sodium is the 6th most abundant element in the earth’s crust to a depth of 16 km.[1-3] Additionally, NIBs undergo reactions that are similar to those of LIBs in terms of ion intercalation and solid-state diffusion, phase transitions, surface film formation, and interfacial charge transfer processes, thereby facilitating the R&D process. The development of high-energy and high-power density sodium-ion batteries is a great challenge for modern electrochemistry. The main hurdle to wide acceptance of sodium-ion batteries lies in identifying and developing suitable new electrode materials. This study presents a composition-graded cathode with average composition Na[Ni0.61Co0.12Mn0.27]O2, which exhibits excellent performance and stability. In addition to the concentration gradients of the transition metal ions, the cathode is composed of spoke-like nanorods assembled into a spherical superstructure. Individual nanorods particles also possess strong crystallographic texture with respect to the center of the spherical particle. Such morphology allows the spoke-like nanorods to assemble into a compact structure that minimizes its porosity and maximizes its mechanical strength while facilitating Na+-ion transport into the particle interior. Microcompression tests have explicitly verified the mechanical robustness of the composition-graded cathode and single particle electrochemical measurements have demonstrated the electrochemical stability during Na+-ion insertion and extraction at high rates. These structural and morphological features contribute to the delivery of high discharge capacities of 160 mAh (g oxide)-1 at 15 mA g-1 (0.1 C rate) and 130 mAh g-1 at 1500 mA g-1 (10 C rate). The work is a pronounced step forward in the development of new Na ion insertion cathodes with a concentration gradient.

References

[1] B. Scrosati, J. Hassoun, Y. K. Sun, Energy Environ. Sci. 2011, 4, 3287.

[2] V. Etacheri, R. Marom, R. Elazari, G. Salitra, D. Aurbach, Energy Environ. Sci. 2011, 4, 3243.

[3] J. Emsley, Nature’s Building Blocks, Oxford University Press, Oxford, UK 2011.
The Impact of Dead Li on Mass Transport, Voltage Profiles, Capacity, and Failure of Lithium Metal Anodes
Authors: Chen Kuan-Hung , Wood Kevin N. , Kazyak Eric , LePage William S. , Davis Andrew L. , Sanchez Adrian J. , Dasgupta Neil P.
Published: February 2020

Currently, Li metal anode development is restricted by low Coulombic efficiency, poor cycle life, and safety concerns. Each of these challenges stem from the extreme reactivity of Li metal and the resulting undesirable interactions at the electrode/electrolyte interface. Dendrites grow during electrodeposition, consuming electrolyte, leading to dead Li formation and capacity fade, and eventually causing short circuiting. The limited knowledge of the dynamically evolving Li metal surface during extended cycling has prevented rational design of methods to mitigate these undesirable behaviors. Our recent work elucidated the correlation of galvanostatic voltage traces with morphology evolution on Li metal anodes during early cycles, providing a “window” into cells which traditionally are difficult to monitor with operando techniques [1]. The present work builds on that understanding by studying the evolution of the voltage trace shape and the dead Li layer over extended cycling in both Li-Li symmetric and full cells containing Li metal anodes (Figure 1).

In this work [2], we focus on understanding: 1) the evolution of the voltage trace from the peaking shape seen in Figure 1a to the arcing seen in Figure 1b during extended cycling in both half and full cells, 2) how the accumulation of a dead Li layer impacts mass transport, and 3) why dead Li causes capacity fade and failure of full cells containing Li metal anodes. Continuous accumulation of dead Li on the anode surface leads to the formation of a tortuous porous interphase. This layer creates larger interfacial concentration gradients which lead to large overpotentials. Based on experimental results and modeling, we provide a detailed understanding of the effects that mass transport through complex interphases has on capacity fade, voltage traces, and failure of Li metal anodes in half and full cell configurations. We demonstrate that these effects at the anode have significant impacts on full cell performance, in many cases driving failure. This result underscores the importance of understanding the dynamic morphology evolution on anode surfaces and shows that Li-Li symmetric cells are a powerful tool to study the underlying physical phenomena occurring during cycling. This study enables evaluation of methods of reducing dead Li formation and rational design of solutions for improved performance in Li-metal batteries, an important step towards making Li metal rechargeable batteries a commercial reality.

References

1. K. N. Wood, E. Kazyak, A. F. Chadwick, K.-H. Chen, J.-G. Zhang, K. Thornton, N. P. Dasgupta, ACS Cent. Sci. 2, 790 (2016).

2. K.-H. Chen, K. N. Wood, E. Kazyak, W. S. LePage, A. L. Davis, A. J. Sanchez, N. P. Dasgupta, Submitted.

Figure 1
Passivated Lithium Metal As Anode Materials for Advanced Battery Applications
Authors: Cha Eunho , Choi Wonbong
Published: February 2020

Lithium (Li) metal electrodes are widely regarded as the promising anodes since their energy densities far exceed those of lithium-intercalated carbon anode materials. However, Li metal anodes are plagued with dendrite formation and electrolyte incompatibility that limits their lifespan and stability within any battery systems that employ them. A promising way to resolve those limitations involves the use of passivating layers to protect the surface of Li metal. This study will explore the mechanism behind the formation of Li dendrite and the passivation of the Li metal surface; it will also discover how coating Li metal with Li ion-conducting layers would effectively protect it from attacks by solvents, contamination, and active species in the electrolyte. Here, we demonstrate the facile method to protect the surface of Li metal with precise structural control. Utilizing symmetric Li-Li cell configuration, the protected Li exhibited stable cycling with minimal polarization at current density of 10 mA cm-2; it also demonstrated over 300% longer cycle life than unprotected Li metal. In addition, a full-cell system using sulfur cathode confirmed an improved capacity retention with our protected Li metal over the cell with bare Li metal for over 300 cycles. The improvement in cycle life and the suppression of lithium dendrite growths through the passivation of Li metal electrodes reveal a new direction for the advancement of Li metal anode in rechargeable batteries.
Requirements for Reversible Extra-Capacity in Li-Rich Layered Oxides for Li-Ionbatteries
Authors: Xie Ying , Saubanere Matthieu , Doublet Marie-Liesse
Published: February 2020

The structural stability and redox mechanism of Li-rich transition metal oxides (LLO) are two very important aspects for high energy density. The former is related to the irreversible loss of lattice oxygen and capacity fading during cycling, while the latter determines the overall capacity of the materials. This paper aims at clarifying the factors governing the structural stability, the extra capacity and the redox mechanism of LLOs upon Li-removal. The results show that the structural stability against oxygen vacancy formation is improved with increasing M-O covalency, while it decreases with increasing thed-shell electron number and with electrochemical extraction of lithium from the lattice. The redox mechanism of Li2-xMO3 electrodes formed by 3d metals or by heavier metals with ad0electronic configuration is related to the electron depletion from the oxygen lone-pairs (localized and non-bonding O(2p) states) leading to an irreversible anionic redox ending with the reductive elimination of O2 upon cycling. For these phases, long-term cycling is predicted to be very unlikely due to the irreversible loss of lattice oxygen upon charging. For the electrodes formed by 4d and 5d metals with intermediate dnelectronic configurations (n ≥2), reversible cationic and anionic redox activities are predicted, therefore enabling reversible extra-capacities. The very dierent redox mechanisms exhibited by Li2-xMO3electrodes are then linked to the delicate balance between the Coulomb repulsions (Uterm) and the M-O bond covalency (Δ term) through the general description of Charge-Transfer vs. Mott-Hubbard insulators. The present findings will provide a uniform guideline for tuning the band structures of Li2MO3phases and thus activating desired redox mechanisms, being beneficial for the design of high-energy density electrode materials for Li-ion battery applications.
Ordered Nickel Nanomesh-Based Electrodes for High Capacity Thin-Film Lithium Ion Batteries
Authors: Zankowski Stanislaw Piotr , Vereecken Philippe M.
Published: February 2020

The growing market of small consumer electronics, such as cell phones, smartwatches or electronic eyewear requires development of small power sources that allow for both satisfactory usage time and fast charging. Lithium-ion batteries (LIBs) are currently the systems of choice thanks to their high energy and power density. However, downscalling these batteries for small device applications still possess a big challenge. Thin-film Li-ion micro-batteries with high (dis)charging rate capability are currently available on the market, but are limited to niche applications such as chip backup power as the total output energy are still far too low for consumer device applications. Also, the manufacturing of thin film batteries requires sophisticated PVD/CVD deposition techniques. To overcome these issues, 3D architecturing of the current collector can be employed [1, 2]. This can provide a system where very thin active materials are stacked over enormously large surface area of a 3D current collector to yield a cell with both high power density (due to reduced materials thickness) and high energy density (thanks to large total volume of the active materials). To minimize the dead volume, it is imperative that the current collectors are both small and have controlled spacing. Herein, we report on the fabrication of ordered nickel nano-mesh (Fig. 1a). The nanostructured cathode is prepared by cost effective electrodeposition method, using anodized aluminum oxide (AAO) as a template for 3D interconnected nanowires. A nickel nanowire mesh with 30 nm-wide nanowires and 80 nm spacing is shown in Fig. 1a. Further, we demonstrate an accurate method to determine the effective surface area based on the electrochemical passivation of nickel. In this example, the current collector contains 71% of empty volume and has the total surface area enhancement reaching up to 97x for the 2.7 μm-long 3D nanoscaffold in Fig. 1a. Next, 25 nm of manganese dioxide was electroplated on the Ni nano-mesh current collector (Fig. 1b). The thin film cathode layer showed 82x higher current and 66x higher charge for lithium extraction in Li+/PC electrolyte as compared to 65nm planar MnO2 electrode (Fig. 1c). Additionally to electrochemical performance, we will discuss the methods we used to mitigate material incompatibility between the current collector and active material during thermal processing, needed for good crystallization of the electroactive layers. Backed with simulation and grazing-incidence XRD data, we will stress the importance of appropriate interface engineering for fabrication of reliable nickel-based nanostructured electrodes.

1. J. F. M. Oudenhoven, L. Bagetto, P. H. L. Notten, Adv. Energy Mater., 2011, 1, p. 10-33.

2. J.Vanpaemel, A. M. Abd-Elnaiem, S. De Gendt, P. Vereecken, J. Phys. Chem. C, 2015, 119 (4), pp 2105-2112

Figure 1
Transformation of Bulk Alloys to Oxide Nanowires and Their Use in a Li-ion Battery Separator
Authors: Yushin Gleb , Lei Danni , Benson James , Magasinksi Alexandre
Published: February 2020

One dimensional (1D) nanostructures offer prospects for enhancing electrical, thermal and mechanical properties of a broad range of functional materials and composites, but their synthesis methods, such as catalyst-assisted vapor deposition, physical vapor deposition, hydrothermal synthesis, the use of sacrificial templates and others, are relatively expensive and difficult to scale. Here we demonstrate direct transformation of bulk materials into nanowires at room temperature and ambient pressure without use of catalysts, corrosive or toxic chemicals, or any external stimuli [1]. The nanowire formation proceeds via a minimization of the strain energy at the boundary of chemical transformation reaction front. We show transformation of multi-micron particles of Al alloy and Mg alloy into alkoxide nanowires of tunable dimensions, which are converted into oxide nanowires upon simple heating in air. The reported approach provides opportunities for ultra-low cost large-scale synthesis of 1D materials and membranes.

Conventional polymer separators for Li-ion batteries (LIBs) suffer from limited mechanical strength and low thermal stability, which may lead to thermal runaway and cell explosion. We produced flexible, binder-free, nonwoven fabric composed of gamma-Al2O3 nanowires, using a simple tape casting technique followed by a heat treatment in air. The overall morphology of the produced fabric is somewhat similar to that of a paper, where the cellulose fibers are replaced with stronger and stiffer Al2O3 nanowires. Owing to the fibrous nature of thus-produced free-standing films and the small diameter of the Al2O3 nanowires, they exhibit good flexibility. This is in contrast to anodized Al2O3 membranes of comparable thickness that are known to be extremely brittle and difficult to handle. Results of electrolyte wetting tests revealed significantly superior performance of Al2O3 paper compared to commonly used commercial olefin (polypropylene) separator or a cellulose fiber separator. The wetting rate of the Al2O3 separator is significantly higher owing to its polar nature, as determined by both the final wetting area and the speed of etting. Thermal stability tests demonstrate the advantage of having a flexible porous ceramic separator with operating temperatures above 800°C, which is important because of rapid heating to high temperatures that may occur in failing LIBs. In contrast, the most commonly used olefin separators typically start melting at around 120°C and oxidize at around 300°C. Finally, the strength of ceramic fibers is known to exceed that of the olefins, which should allow formation of thinner separators in automotive LIBs without sacrifice of their mechanical properties.

[1]. D Lei, J Benson, A Magasinski, G Berdichevsky, G Yushin, Transformation of bulk alloys to oxide nanowires, Science 2017, 355 (6322), 267-271.
Electrochemical Characteristics of Carbon Based Cathode Material with Molybdenum Sulfide Catalyst for Lithium Air Batteries
Authors: Kim Jiyeon , Choi Yusong , Griep Mark H. , Jang Yoonhee , Cho Janghyeon , Yoo Hyeryun
Published: February 2020

Lithium air batteries have been recognized as one of expected next-generation military power sources, supplying power for a long time even in independent extreme environment. For the commercialization of lithium air batteries, it is essential to search for a cathode material capable of stable and efficient on electrochemical reaction at the interface with the electrolyte. Among the numerous cathode materials, such as carbon nanostructures, expensive noble material, and metal oxides, carbon-based materials are intensively researched as candidate oxygen electrode for lithium air batteries thanks to the engineering pore size and the competitive cost. However, they suffer from degradation of the carbon structure due to the formation of side products limiting the benefit of theirs oxygen reduction reaction characteristic. Recently, molybdenum sulfide(MoS2) has been received the attention as a promising catalyst to maximize oxygen reduction and evolution reactionon the carbon-based cathode. In this study, various shaped MoS2 were grown on activated carbon felt, and their electrochemical properties were compared and analyzed in order to attain a way to maximize the electrochemical reaction in electrode. We also investigated the structure and microstructure of the electrodes before and after discharge test to understand the relation between the performance of cathode materials under various synthesis condition of the catalyst for lithium air batteries.
Electrochemical Investigations on Arylsilicon and Aryltin Hydrides and Their Resulting Polymers
Authors: Biedermann Judith , Zeppek Cathrin , Torvisco Gomez Ana , Hanzu Ilie , Uhlig Frank
Published: February 2020

Silicon and tin are interesting candidates for anode materials in Lithium ion batteries as they have some of the highest theoretical specific capacities (4200 mAh g-1 for silicon and 991 mAh g-1for tin).[1] This advantage is counteracted by a major volume expansion with subsequent contraction during lithiation and delithiation. This expansion is causing the electrode to pulverize, lose electrical contact and thus leading to a quick fade in capacity. Pulverization may be avoided when nanoparticles or nano-sized polymers are used as they are small enough to allow “active material breathing” and thus to evade a breakdown of the electrode.[2]

Organosilicon and organotin hydrides have been studied as precursors in the formation of nano-sized polymeric materials which consist of a backbone of covalently bonded metal atoms.[3] These materials feature an increased degree of electron delocalization and may therefore be interesting for the use in charge-transfer devices and Li-ion batteries.[4] We focused on the synthesis, characterization and possible application of differently substituted arylsilicon and aryltin hydrides and their respective nanoparticles and nano-sized polymers.[5]

Moreover we synthesized aryl-substituted silicon and tin hydrides of the types R3EH, R2EH2 and REH3 (R = phenyl, 1-naphthyl; E = Si, Sn) as precursor materials and characterized them using cyclic voltammetry. The precursors were then pyrolysed or polymerized, respectively, and the resulting nanoparticles were incorporated within anodes of Li-ion batteries.

Herein we report first electrochemical characterization of differently aryl-substituted silicon and tin hydrides using cyclic voltammetry methods. Additionally, these precursor materials as well as their respective nanoparticles were tested as anode materials in Li-ion half-cells.

References:

[1] a) C.K. Chan et al., Nat. Nanotechnol., 2008, 3, 31-35. b) B. Veeraraghavan, A. et al., J. Electrochem. Soc., 2002, 6, A675-A681.

[2] X. Xiao et al., Adv.
Funct. Mater., 2015, 25, 1426-1433.

[3] a) F. Choffat, P. Smith, W. Caseri, J. Mater.
Chem., 2005, 15, 1789-1792. b) K. Schittelkopf, R.C. Fischer, S. Meyer, P. Wilfling, F. Uhlig, Appl. Organomet. Chem., 2010, 24, 897-901.

[4] a) S. Adams, M. Dräger, Main Group Met. Chem., 1988, 11(3), 151-180. b) F. Choffat, P. Smith, W. Caseri, Adv. Mater, 2008, 20, 2225-2229.

[5] a) C. Zeppek, Dissertation, 2015, University of Technology Graz. b) C. Zeppek, et al., J. Organomet. Chem., 2013, 740, 41-49. c) C. Zeppek, et al. in preparation.
A Hydrocarbon Cathode for Dual-Ion Batteries
Authors: Rodríguez Pérez Ismael Antonio , Jian Zelang , Waldenmaier Pieter K. , Palmisano Joseph W. , Chandrabose Raghu Subash , Wang Xingfeng , Lerner Michael M. , Carter Rich G. , Ji Xiulei
Published: February 2020

The paradigm of battery research has begun to shift to exploring electrode materials that are completely renewable, where such electrode materials ideally do not contain any metallic elements. We have demonstrated, for the first time, a polycyclic aromatic hydrocarbon (PAH) - crystalline and readily available coronene - exhibiting highly reversible anion-storage properties. Conventional graphite anion insertion electrodes operate at potentials > 5.0 V vs Li+/Li, requiring additives and the use of ionic liquids. The coronene electrode shows flat plateaus at 4.2 V (charge) and 4.0 V (discharge) in a standard alkyl carbonate electrolyte and delivers a reversible discharge capacity of ~ 40 mA h g-1. Ex situ characterization reveals that coronene retains its crystalline structure and chemical bonding upon PF6
- incorporation. Coronene-PF6 electrodes show impressive cycling stability: 93% capacity retention after 1600 cycles. The discovery of the reversible anion-storage properties of coronene may open new avenues toward dual-ion batteries based on PAHs as electrodes.
Investigation of Electrochemical Performance of Li-O2 Batteries Using Catalyst Containing Carbon Nanotube Cathodes
Authors: Chawla Neha , Chamaani Amir , Safa Meer , El-Zahab Bilal
Published: February 2020

Batteries with high specific energy densities have attracted a lot of attention due to their demand in electric vehicles (EVs). Due to the increase in demand for energy storage devices for applications such as load-levelling of electrical energy supply and demand propulsion for electric vehicles and microelectro-mechanical devices, the research for new classes of electrode materials that provide high energy, high power and cycle life longer than lithium-ion batteries is being motivated. Lithium air batteries have high specific energy density and they can achieve four times higher energy density than the current lithium ion batteries. The search for high energy density batteries has motivated the research in lithium-air batteries.

Catalysts have been shown to improve both the battery capacity and the recyclability of these batteries when used in cathodes. Several catalysts have been discovered for lithium air batteries. Debart et al. used several catalysts for lithium oxygen batteries with non-aqueous electrolyte. The electro-catalysts used by them included Pt, La0.8Sr0.2MnO3, Fe2O3, NiO, CuO, CoFe2O4. Co3O4 exhibited highest discharge capacity and best cycling performance. Later Debart et al. examined manganese oxides as catalysts for lithium oxygen batteries. Mn3O4, bulk Mn2O3, bulk α, β, λ, γ-MnO2, α-MnO2 nanowires and β-MnO2 nanowires were used as catalysts. The air cathode with α-MnO2 as the catalyst showed the highest capacity of about 3000 mAh/g (carbon) Lu et al. reported ORR studies on polycrystalline metal catalysts of palladium, platinum, ruthenium, gold and glassy carbon surfaces in non-aqueous electrolyte.

In our study, we investigate various modes of loading palladium-based catalysts and their effect on the capacity and round-trip efficiency of lithium-air batteries. Our aim is to increase the first discharge capacity, improve the recyclability, increase capacity retention and improve the recyclability of the battery. The loading and morphology the catalyst-CNT cathode is studied using transmission electron microscopy. Electrochemical testing using electrochemical impedance spectroscopy and charge-discharge cycling is also investigated. Voltammetry, Raman spectroscopy, FTIR, XRD, UV/Vis spectroscopy and visual inspection of the discharge products using scanning electron microscopy confirms the increased stability of the electrolyte due to this encapsulation and suggest that this approach could lead the increasing Li-O2 battery capacity and cyclability performance.
Parasitic Reactions in Nano-Sized Silicon Anodes for Lithium-Ion Batteries
Authors: Gao Han , Xiao Lisong , Plümel Ingo , Xu Gui-Liang , Ren Yang , Zuo Xiaobing , Wiggers Hartmut , Amine Khalil , Chen Zonghai
Published: February 2020

When designing nano-Si electrodes for lithium-ion batteries, the detrimental effect of the c-Li15Si4 phase formed upon full lithiation is often a concern. In this study, Si nanoparticles with controlled particle sizes and morphology were synthesized and the parasitic reactions of the metastable c-Li15Si4 phase with the non-aqueous electrolyte was investigated. The use of smaller Si nanoparticles (~ 60 nm) as well as the addition of fluoroethylene carbonate additive played decisive roles in the parasitic reaction such that the c-Li15Si4 phase could disappear at the end of lithiation. This suppression of c-Li15Si4 improved cycle life of the nano-Si electrodes but with a little loss of its specific capacity. In addition the characteristic c-Li15Si4 peak in the dQ/dV plots can be used as an early-stage indicator to the cell capacity fade during cycling. Our findings can contribute to the design guidelines of Si electrodes and allow us to quantify another factor to the performance of the Si electrodes.
Uniformly Thin and Large Surface Modification of Lithium Anode for Improving Cycling Performance of Lithium Metal Batteries
Authors: Moon Yong-Bok , Kim Jae-Hong , Woo Hyun-Sik , Kim Dong-Won
Published: February 2020

Rechargeable lithium batteries using lithium metal as a negative electrode are attractive candidates for high energy density power sources, because the lithium metal offers a high specific capacity and possesses a low electrochemical potential.1,2 However, the development of rechargeable lithium metal batteries has been hindered for several decades by the high reactivity of lithium metal toward liquid electrolytes and the occurrence of dendrite growth during charge and discharge cycles. The formation and growth of lithium dendrites result in safety and cycle life problems. Additionally, continuous generation of the new solid electrolyte interphase (SEI) layer on lithium metal causes uncontrolled reductive decomposition of the organic electrolyte and gradual loss in capacity and cycling efficiency with repeated cycling. Therefore, protection of lithium metal and the formation of a stable SEI layer on the lithium electrode are very important for developing lithium metal batteries with good capacity retention and enhanced safety. In this work, a prospective approach for protecting a lithium metal is presented by spray coating with a conductive poly(3,4-ethylenedioxythiohene)-co-poly(ethylene glycol) (PEDOT-co-PEG) and inorganic particles (AlF3), which allows for lithium ion diffusion and restricts the access of the reactive solvents to the lithium surface. The protective composite layer played a positive role in reducing the reductive decomposition of the electrolyte and suppressing the dendrite growth of lithium during cycling. As a result, the surface modification of lithium electrode with PEDOT-co-PEG and AlF3 significantly improved the cycling stability of the lithium metal batteries.

 

References

1. J.M.Tarascon and M.Armand, Nature, 539, 414 (2001).

2. D.Linden and T.B.Reddy, Handbook of Batteries, 3rd Edition, McGraw-Hill, New York (2003).
Silicon-CNT Composite for High Energy Density Li-Ion Batteries
Authors: Ventrapragada Lakshman K , Parajuli Prakash , Kousaalya A B , Pilla Srikanth , Podila Ramakrishna , Rao Apparao M
Published: February 2020

Rechargeable batteries (e.g., Li-ion) are widely used to power a number of portable electronic devices such as mobile phones and laptops. Li-ion batteries (LIBs) in particular have revolutionized electric vehicle technology, nonetheless, they suffer from poor energy and power densities, which ultimately limit the driving range and increase the cost. Recently, silicon (Si) anode has attracted a considerable attention from battery researchers as an alternative to conventional graphite anode due to its high specific capacitance (4200 mAh g-1) corresponding to Li22Si5. However successful commercialization of Si anodes in battery packs is hindered by the irreversible capacity loss during cycling associated with volume expansion (~300%), finally leading to electrode failure. In recent times, there have been a number of reports claiming high specific capacities for Si composites but they involve complex synthesis steps leading to higher cost. In this poster, we will discuss our approach of making a composite with CNTs and commercial Si using ultrasonication method. Carbon nanotubes (CNTs) have excellent electrical conductivity and mechanical stability. The composite electrodes when assembled into a battery showed excellent electrochemical performance: albeit small losses in coulombic efficiency during initial six cycles, they retained 100% efficiency for more than 150 cycles. This could be attributed to the inclusion of CNTs which form a flexible network around Si particles, and facilitates volume expansion/contraction during reduction/oxidation of the electrode. Such modification of Si anodes can be seamlessly integrated into commercial manufacturing.