bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toward a Metallic Silicon Anode for Practical Lithium-Ion Battery Applications
Authors: Ryu Jaegeon , Park Soojin 
Published: February 2020

The current state-of-the-art batteries comprising graphite-based anodes are facing its performance limit for the use in automotive applications, thus urging to develop electroactive materials with high capacity and low operating potentials [1]. Si has shown great promise as a next-generation anode, meeting the above requirements in natural abundance. However, unavoidable large volume change upon lithium insertion/extraction causes particle fracture and disintegration of the electrode, resulting in fast degradation of battery along with poor electric conductivity being the main hurdle for fast-chargeable battery design [2]. Recently, interesting breakthroughs have been proposed principally in nanostructuring of Si, composite formation with conductive carbons and mechanically stable binders, which achieved long-term cycle stability and rate capability [3]. Yet, these approaches lead to lowering the electrode density, initial Coulombic efficiency and energy density of battery and thus utilizing the Si microparticles can be rather feasible toward a practical system while stress-driven particle degradation becomes more serious. The existing technologies have focused on coalescing the fractured particles, not preventing itself, and have not considered ionic diffusion of Li-ion across the microparticles as well as the electronic conduction.
Herein, we propose the material design concept of Si microparticles by integrating the chalcogen component into the bulk structure through a low temperature doping strategy. The low electric conductivity of intrinsic Si (~10-4 S m-1) with a near-insulator property undergoes a transition into the metallic state via this new method unlike other dopants of boron or phosphorous that only gives extra charge carriers without insulator-to-metal transition. In addition to electronic conduction, the chalcogen chains restrict the saturation of Si dangling bonding during recrystallization process of low temperature doping and create the internal channels inside the crystalline Si lattice. The incorporation of Li-ion channels further increases Li-ion diffusivity without any barriers in case of undoped Si microparticles due to the interfaces of lithium silicide and amorphous Si. Interestingly, chalcogen chains can sustain its internal structure with high flexibility and robustness which is directly corroborated by microscopy analysis, and lithium-induced intermediate can maintain the metallic nature at the interfaces that enhance the Li-ion diffusion over the cycles. Further, the porous but minimized surface area of Si structures increases the initial reversibility, extends the cycle life of battery up to hundreds of cycles with a high structural stability and facilitates fast-charging ability.

[1] A. S. Arico, P. Bruce, B. Scrosati, J. M. Tarascon, W. Van Schalkwijk, Nat. Mater. 2005, 4, 366.
[2] H. Wu, Y. Cui, Nano Today 2012, 7, 414.
[3] J. Ryu, T. Chen, T. Bok, G. Song, J. Ma, C. Hwang, L. Luo, H.-K. Song, J. Cho, C. Wang, S. Zhang, S. Park, Nat. Commun. 2018, 9, 2924
Characterisation and Initial Purification Studies of Recovered Electrode Material from EVS
Authors: Driscoll Laura Louise 
Published: February 2020

Li-ion batteries have dominated the portable electronics’ market as the energy storage medium of choice for many years. With increasing concerns related to climate change and the increasing variety of applications in which these batteries can be used, an inevitable increase in demand for the raw materials required to assemble such batteries would be expected. This has led to increasing concern that the virgin materials may be depleted considerably by 2050 if demand continues to rise as predicted.[1]
With the government’s new environmental strategy pushing for the electrification of motor vehicles, with the aim of the majority vehicles on Britain’s roads to be electrically powered by 2030, methodologies must be developed in order to recycle these batteries once they reach end of life in order to reclaim the critical elements. Not only must these strategies be able to recover key elements such as Co and Li efficiently but they must also be able to deal with the wide variety of chemistries currently implemented within the electric vehicle market. The ultimate aim of the ReLiB project is to develop short route recycling methods which can reclaim the material for reuse in pristine batteries. This poster will discuss the initial characterisation and purification/reclamation of electrode materials recovered from batteries that would be destined to enter the recycling chain.
[1] A. Pehlken, S. Albach, T. Vogt, Is there a resource constraint related to lithium ion batteries in cars?, Int. J. Life Cycle Assess. 22 (2017) 40–53. doi:10.1007/s11367-015-0925-4.
Electrodeposition of Sn/SnO2 Composite Materials As Anode Material for Lithium Ion Batteries and the Micro-Mechanical Property
Authors: Chang Tso-Fu Mark , Tanabe Mana , Chen Chun-Yi , Sone Masato 
Published: February 2020

Sn/SnO2 composite materials are promising anode materials in lithium ion battery. Electrodeposition with supercritical CO2(sc-CO2) emulsified electrolyte (EP-SCE) is an effective method in controlling morphology (Ni [1], Cu[2], and Co[3]) and crystallinity (ZnO [4]and TiO2 [5]) of electrodeposited materials. Sc-CO2 is CO2 at temperature and pressure above its critical point, which is 304.1 K and 7.38 MPa. CO2 is non-polar, therefore, the solubility of metal salts and electrical conductivity are both very low in sc-CO2. In order to conduct electrochemical reactions, surfactants are used to form emulsified electrolyte.
Co-deposition of SnO2 along with electrodeposition of metallic Sn can occur at the same time in a SnCl2 based electrolyte containing NO3
- ions [6]. The EP-SCE is expected to be effective in controlling concentration and properties of the SnO2 in metallic Sn film. In this study, Sn/SnO2 composite films are prepared by electrodeposition with supercritical CO2 (sc-CO2) emulsified electrolyte, and the mechanical properties in micro-scale are evaluated by compression test of micro-pilliars fabricated from the Sn/SnO2 composite film for practical applications.
Details of the high pressure electrochemical apparatus can be found in a previous study [1]. The electrolyte is composed of 0.22 M SnCl2, 0.015 M HCl and 0.31 M (NH4)3C6H5O7. The current density applied is varied from 2.8 to 17.3 mA/cm2. For the EP-SCE, the surfactant is C12H25(OCH2CH2)15OH. 0.2 vol.% of the surfactant is used to form the sc-CO2 emulsions. 20 vol.% of CO2 at 343 K and 15 MPa under agitation are used to ensure the formation of a stable emulsion. Electrodeposition without the sc-CO2 emulsions at ambient condition (CONV) was also conducted to be used as a comparison.
Surface morphology of the films prepared by EP-SCE were very smooth and compact, and the CONV films were porous. On the other hand, there is not much different in the average grain size between the EP-SCE and CONV films, which was about 50 μm for both the EP-SCE and CONV films. The oxygen content in the EP-SCE films can be up to 28.3 at.% by adjusting the electrodeposition parameters.
Micro-pillars with a 20×20 μm2 cross-section and a height at 40 μm were fabricated by focus ion beam from the deposited films. The yield stresses were ranged from 10 to 40 MPa when the current density changed.
Acknowledgment:
This work was supported by JST CREST Grant Number JPMJCR1433.
Reference:
[1] Electrochim. Acta 55 (2010) 6469-6475
[2] Thin Solid Films 529 (2013) 25-28
[3] J. Electrochem. Soc. 162 (2015) D423-D426
[4] J. Phys. Chem. C 117 (2013) 25596-25603
[5] Electrochem. Commun. 33 (2013) 68-71
[6] J. Alloys Compd. 403 (2005) 335-340
Melt-Processing of Electrodes for Lithium-Ion Batteries: A New Solvent-Free Approach
Authors: EL Khakani Soumia , Verdier Nina , Rynne Olivier , Ciszewski Dorian , Lepage David , Prébé Arnaud , Ayme-Perrot David , Badia Antonella , Dollé Mickael , Rochefort Dominic 
Published: February 2020

Lithium-ion is currently the leading technology for electrochemical energy storage, especially in the transportation sector. The electrification of vehicles through the use of lithium-ion batteries (LiBs) is at the center of the world efforts to decrease atmospheric pollution by reducing CO2 emission. Due to the high efficiency of electrical motors, a net reduction in greenhouse gases is achieved upon electrification of vehicles even in areas where electricity is generated from fossil fuels. Yet, the rapidly growing production of LiB brings new concerns on the environmental cost of the technology. The analysis of a complete their life cycle, from mining precursors to recycling batteries at the end of their life, reveals that several steps of the cycle can be improved to further reduce the environmental footprint of lithium-ion batteries. It is in this context that our group got interested in developing alternative approached to electrode fabrication, a key aspect of LiB manufacturing. Currently, most of the electrode fabrication processes involves the use of organic solvents, typically N-methyl-2-pyrrolidone (or NMP), which is toxic and costly. As such, a considerable effort is spent during electrode fabrication to recuperate NMP vapors and prevent exposure to the workers and environment. Avoiding the use of any solvents during electrode fabrication would not only minimize the environmental impact but would also result into lower energy consumption.
This contribution presents a study of a new solvent-free melt process technique to LiB electrode fabrication through the use of elastomeric binders. The impact of formulation on active material dispersion, microscopic morphology, electronic percolation and porosity will be discussed. With such parameters optimized, the electrochemical response of composite electrodes based on LiFePO4 and Li4Ti5O12 active materials were characterized both individually and as full cells. The battery performance will be compared with PVDF-based electrodes made with a conventional approach.
Li-Rich Cathode Material Enhancement through Atomic Surface Reduction
Authors: Evenstein Eliran , Sharma Rosy , Haber Shira , Leung Kevin , Leskes Michal , Noked Malachi 
Published: February 2020

Lithium Ion batteries (LIB) have revolutionized the portable electronics industry for over two decades, with high energy density, cycle capability and safety. In recent years the LIBs are the lead candidate to fuel the power demands of electric vehicles (EVs). However, current generation cathode materials fall short in terms of energy density for fulfilling the demands of future applications (energy storage, EVs, etc.).
Li-Rich materials are the main contenders to become the next generation rechargeable li ion cathode material. Li-Rich materials are a family of layered materials which consist of Li, Mn, Co and Ni Oxides. One promising compound of Li-rich material contains two phases: X(Li2MnO3) - (1-x)(LiMnaNibCocO2) where (a+b+c=1) . These materials exhibit high capacity (~250mAhrg-1 vs. ~170mAhrg-1 of current Generation cathodes), good stability and are safe for use. However, upon cycling, the Li-Rich cathodes suffer from voltage decay, which is currently attributed to be evolution of O2 which causes a Redox process on the surface.
We propose a new method for enhancement of the Li-rich cathode stability by controlled surface modification. The modification aims to control the oxygen evolution during cycling and thus control the voltage decay. This method shows improvement in the voltage stability during cycling and capacity retention.

Figure 1
In Situ NMR Analysis of Lithium Metal Surface Deposits from Electrolytes with Varying Salt Concentrations
Authors: Küpers Verena , Kolek Martin , Bieker Peter , Winter Martin , Brunklaus Gunther 
Published: February 2020

Lithium metal constitutes a promising anode material, based on its high theoretical specific capacity (3 860 mAh g−1), and low electrochemical potential (−3.04 V vs. SHE). Non-homogeneous lithium deposition, however, may lead to the formation of reactive high surface area lithium (HSAL) upon cycling, eventually yielding losses of active material, safety risks, and insufficient cycling efficiency. HSAL with e.g. needle-like structure does not only cause higher capacity losses based on side reactions and solid electrolyte interface (SEI) formation, but also could result in internal short circuits by penetration of separator layers. In contrast, low surface area lithium (LSAL) such as nodule-like deposits[1] may reduce unwanted side reactions as well as safety risks. The actual microstructure of lithium deposits is governed by extrinsic factors including cell pressure, temperature, current densities, as well as surface properties of lithium metal electrodes but also the explicit choice of electrolyte constituents, and is therefore crucial for the overall cell performance.[2] In this work, highly concentrated electrolytes are exploited to achieve improved cycling stability and reduced HSAL formation, where the formation of a highly robust SEI, more uniform lithium deposits, fewer side reactions on the anode surface, as well as higher viscosity of the electrolytes were identified as key factors.[1, 3]
Electrochemical in situ investigations, scanning electron microscopy (SEM) [4] and in situ
7Li nuclear magnetic resonance (NMR) spectroscopy [5, 6] are applied to in detail elucidate lithium deposition phenomena in symmetrical Li/Li cells. In addition to SEM data, in situ
7Li NMR constitutes an alternative, highly viable spectroscopic method that affords (semi-) quantitative and qualitative monitoring of lithium microstructure growth upon cycling, thereby unraveling critical processes during electrodeposition while delivering counterstrategies for unrestrained HSAL growth and options for achieving significantly improved electrochemical performance and life time of the considered cells.
[1] J. Qian, et al., Nature Communications, 6 (2015) 6362.
[2] X.-B. Cheng, et al., Chemical Reviews, 117 (2017) 10403-10473.
[3] L. Suo, et al., Nature Communications, 4 (2013) 1481.
[4] G. Bieker, et al., Physical Chemistry Chemical Physics, 17 (2015) 8670-8679.
[5] H.J. Chang, et al., The Journal of Physical Chemistry C, 119 (2015) 16443-16451.
[6] R. Bhattacharyya, et al., Nature Materials, 9 (2010) 504-510.
Enhanced Supercapacitor Performance By Tuning the Wettability of Vapor Grown Carbon Nanofibers Using Oxygen Plasma Treatment
Authors: Avasthi Piyush , Arya Nitika , Balakrishnan Viswanath 
Published: February 2020

Carbon based materials have been explored widely for supercapacitor applications in commercial perspective. Despite that their poor performance in terms of volumetric and gravimetric capacitance seems bottleneck in high performance supercapacitor device applications. The major reason for the same is their poor wettability. Generally, carbon based materials are found to be hydrophobic which limits their electrode – electrolyte interfacial interaction and hence, suppresses the charge storage performance.
In this work, we report vapor grown carbon nano fibers (CNF) at large scale using chemical vapor deposition adopting simple catalytic approach. CVD grown CNF showed crystalline 1 D morphology confirmed by detailed electron microscopy. As grown CNF shows hydrophobic nature. Supercapacitor measurements revealed 14.6 mF/cm2 aerial capacitance. In order to improve electrode - electrolyte interfacial interaction, the wettability factor has to be improved and hence O2 plasma treatment has been adopted to convert hydrophobic CNF into hydrophilic. Time dependent contact angle measurements revealed the absence of ageing effect due to changes in microstructure after plasma treatment which was confirmed by electron microscopic investigations. Further, comparative electrochemical measurements proved remarkable enhancement in supercapacitor performance of plasma treated CNF in terms of aerial capacitance (162.5 mF/cm2) compared to as grown CNF. The change in wettability led to superior supercapacitor performance along with high Coulombic efficiency. Taking this work to one step further CNF were uniformly encapsulated with MoO3 in 1 D core – shell fashion where CNF acts as core and MoO3 acts as shell in the subsequent CVD process. This approach provides a path in developing low cost - high energy density supercapacitor using simple methods.
A Redox-Flow-Battery Based on Aqueous Polyoxometalate Electrolytes
Authors: Pfanschilling Felix Leon , Friedl Jochen , Holland-Cunz Matthäa Verena , Cording Faye , Schricker Barbara , Fleck Robert , Wolfschmidt Holger , Stimming Ulrich 
Published: February 2020

In order to utilise intermittent renewable energy sources like wind and solar power more efficiently, flexible and inexpensive electricity storage capabilities are required. One particularly well-suited option for this task are Redox-Flow-Batteries (RFBs). RFBs are the only type of battery where power and capacity can be scaled independently, thus providing high flexibility and versatile applications.
However, the prevailing technology, the all vanadium system, comprises low energy and low power densities. We investigate two polyoxometalates (POMs), [SiW12O40]4- and [PV14O42]9-, as nano-sized electron shuttles.1 We show that these POMs exhibit fast redox kinetics (electron transfer constant k
0 ≈ 10-2 cm s-1 for [SiW12O40]4-), thereby enabling high power densities. Furthermore, we could show that these POMs exhibit some more favourable properties for their use in a battery, like high solubility, multiple redox-centres per molecule and a high (electro)chemical stability, which lead to high energy densities and long cycle lifetimes. Water as a solvent provides inherent safety to the system, as no flammable electrodes or electrolytes are used.
In collaboration with Siemens AG, we were also able to scale up the presented system from a 25 cm2 lab cell to a cell with 1400 cm2.2 Cycling over a period of nearly three months provided some very promising results, including a coulombic efficiency of nearly 100%. Post-cycling analysis of the electrolytes indicated no sign of degradation and the observed capacity loss of 0.011% per cycle could be attributed to air oxidation. The energy efficiency dropped from 86.1% to 85.1% over the course of 1400 cycles, again showing a highly stable performance.

References

1 J. Friedl,M. V. Holland-Cunz, F. Cording, F. L. Pfanschilling, C. Wills, W. McFarlane, B. Schricker, R. Fleck, H. Wolfschmidt, U. Stimming, Energy Environ.
Sci., 2018, 11 (10), 3010–3018. https://doi.org/10.1039/C8EE00422F
2 J. Friedl, M. V. Holland-Cunz, F. L. Pfanschilling, R. Fleck, B. Schricker, H. Wolfschmidt, U. Stimming, submitted.
Spherical Si-Nb2O5-C Composite As Anode Materials for Li Secondary Batteries
Authors: Park Dahye , Kim Jae-Hun 
Published: February 2020

In recent years, Li-ion batteries have attracted much attention as the demand for electronics and electric vehicles has increased. Currently, graphite is used as anode materials for Li-ion batteries because of its good cycle performance and reasonable cost. However, graphite has a relatively low specific capacity of 372 mAhg-1 due to its lithium storage mechanism. The low theoretical capacity of graphite does not meet the consumer's need for batteries with high capacity. Therefore, development of new anode materials with high capacity are strongly required. Among diverse Li storage materials that can replace graphite, Li-alloy based materials including group IV elements have been widely researched due to their high theoretical capacity. In particular, silicon has attracted great attention as anode materials for Li-ion batteries due to its high capacity and natural abundance. However, silicon anodes generally suffer from volume expansion during the Li insertion and extraction process, which results in poor cycle performance. To overcome the problem, strategies to suppress the volume expansion of silicon should be suggested.
In this work, we synthesized carbon-coated niobium oxide-silicon composites. Niobium oxide (Nb2O5) has various crystalline polymorphs such as pseudo-hexagonal (TT-Nb2O5), orthorhombic (T-Nb2O5), tetragonal (M-Nb2O5) and monoclinic (H-Nb2O5). These various crystalline polymorphs of Nb2O5 can be prepared by varying the heat treatment temperature, of which orthorhombic structure is favorable for fast Li ions storage. T-Nb2O5 exhibits excellent rate performance during cycling due to its Li insertion/desertion mechanism. However, T-Nb2O5 has a relatively low capacity and thus, silicon and T-Nb2O5 were combined to obtain a high capacity and stable cycle performance. In addition, to increase the electrical conductivity of both silicon and T-Nb2O5, carbon incorporation was employed. First, niobium oxide-silicon composite with micrometer-sized spherical structure was prepared by a solvothermal method. In the microsphere, nanosized Si and Nb2O5 were uniformly distributed. Then, the heat treatment was done with naphthalene at 800℃ to perform both phase transformation to T-Nb2O5 for fast Li transport and carbon coating for cycle performance and enhanced electrical conductivity. As a result, a nanometer-thick carbon layer was coated on the surface. Electrochemical test results exhibited that the synthesized electrode materials showed a high reversible capacity, excellent cycle life, and good rate performance as anode materials for Li rechargeable batteries.
Impact of a Maturation Procedure on the Morphological Dynamics of Si-Based Anodes for Li-Ion Batteries Characterized By I
n-Situ Synchrotron X-Ray Tomography
Authors: Vanpeene Victor , Villanova Julie , King Andrew , Lestriez Bernard , Maire Eric , Roué Lionel 
Published: February 2020

Thanks to its theoretical capacity ten times higher than graphite (3579 mAh g-1 for Li15Si4
versus 372 mAh g-1 for LiC6), substituting graphite by silicon as anode material in lithium-ion batteries is an attractive way to increase their energy density. However, the huge volume expansion/contraction of silicon (up to ~300%) during its lithiation/delithiation causes major morphological changes of the electrode, which severely degrade its cyclability. In this communication, the dynamics of their expansion and contraction, of their cracking in the bulk and of their debonding at the interface with the current collector are characterized by in situ synchrotron X-ray computed tomography. Two electrodes made with micrometric silicon material are compared: one fabricated according to a standard process and the other one prepared with a maturation step, which consists in storing the electrode in a humid atmosphere for a few days before drying and cell assembly [1]. Various morphological parameters are quantified and followed during the first lithiation/delithiation of the electrode, namely (i) the dimensional change of the electrode, (ii) the volume fraction, size and connectivity of the segmented solid, gas and electrolyte phases, (iii) the volume fraction, size and connectivity of the produced macrocracks, (iv) the surface area of the produced delaminated zones from the current collector and (v) the variation of the Si inter-particle distances. All morphological degradations are significantly restrained for the matured electrode, confirming the great efficiency of this maturation step to produce a more ductile and resilient electrode architecture, which is at the origin of the major improvement in their cyclability.
[1] C.R. Hernandez, A. Etiemble, T. Douillard, D. Mazouzi, Z. Karkar, E. Maire, D. Guyomard, B. Lestriez, L. Roué, Adv. Energy Mat.
2017, 8, 1701787.

Figure 1