bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiconductive Behavior of Anodic Titanium Oxide Films with Different Thicknesses
Authors: Fujimura Eri , Fujioka Yuhei , Tsuchiya Hiroaki , Fujimoto Shinji 
Published: February 2020

The high corrosion resistance of metal in aqueous environment depends on a thin oxide film formed on its surface. Oxide films on many metals and alloys exhibit the semiconductive property that is considered to be related to corrosion behavior. Therefore elucidating the semiconductive property of oxide film is necessary to understand corrosion resistance of metals and alloys. In order to discuss the semiconductive property of oxide film, in-situ analytical techniques are desired as the denature of the oxide film during evaluation is avoided. Photoelectrochemical response and electrochemical impedance spectroscopy have been applied to study the semiconductive property of oxide film in-situ. In the present work, the semiconductive property of anodic Ti oxide films with different thickness was analyzed using the techniques. Materials were pure Ti discs embedded into epoxy resin. Prior to experiments, its surface was mirror-finished, then ultrasonically cleaned in methanol, ethanol and deionized water for 5 min, successively. The mirror-finished Ti surface was anodized at various potentials ranged from 3 V to 7 V for 60 min in a 0.01 M Na2SO4 solution and phosphate buffer solution, then examined with electrochemical impedance spectroscopy and photoelectrochemical response.
For the electrochemical impedance spectroscopy, the capacitance of space charge region was measured and analyzed to estimate donor density and flat band potential. The donor density decreased and the flat band potential increased with increasing film formation potential for all samples. This result indicates that the electronic property of the oxide films is correlated with the film formation potential. In the photoelectrochemical response, a photocurrent exhibited similar transients under all conditions. A spectrum of the photocurrent was separated into two components; a spike photocurrent and a subsequent steady photocurrent. At high measuring potentials, spike charge estimated from the spike photocurrent and the steady photocurrent decrease with increasing the film formation potential. At lower potentials, on the other hand, the spike charge and the steady photocurrent increase with increasing the film formation potential. This result suggests that not only film formation conditions but also measurement conditions influence the photoelectrochemical response. In the presentation, the results will be discussed based on results for electrochemical impedance spectroscopy.
A Novel Ceramic-Polymer Composite Electrolyte for Lithium Batteries
Authors: Richter Felix Herrmann , Zekoll Stefanie , Marriner-Edwards Cassian , Hekselman Aleksandra K. , Kasemchainan Jitti , Cai Dongyu , Wallace Robert , Thijssen Job H. J. , Bruce Peter G. 
Published: February 2020

Lithium metal is being intensively pursued as an anode due to its high specific capacity. However, dendrite formation, Li loss and short circuiting upon cell cycling presently impede its use. Furthermore, the flammability of liquid electrolytes poses a severe safety hazard. Replacement of organic liquids by solid electrolytes could pave the way for using lithium metal, simultaneously improving specific energy and battery safety.
Efforts continue on ceramic electrolytes. Challenges include the formation and manufacture at scale of sufficiently thin, highly dense, pinhole-free sheets of ceramic electrolytes, required for high power devices. Such electrolytes must also maintain contact with the solid electrodes while inhibiting Li dendrites and be durable towards volume changes of the electrodes as well as to external shock.
Polymer electrolytes have been developed for a number of years. They can exhibit good adhesion and contact to the electrodes, but typically have lower conductivity and limited capability of suppressing dendrite formation.[i]
To date, ceramic and polymer electrolytes remain a challenge. Composites of particulate ceramics embedded within polymer electrolytes have been investigated to improve the conductivity and mechanical properties.
[ii]
Our approach is to create ordered composite electrolytes, which allows modification of the mechanical properties of the composite while retaining good overall ionic conductivity.
The conductivity of the polymer-ceramic composite is 1.5E-4 S/cm at 25 °C. The results for different ceramic-polymer compositions indicate that the mechanical properties of the composite can be modified by the presented approach. Mechanical testing and the results of galvanostatic cycling will be reported.

[i] G. M. Stone, S. A. Mullin, A. A. Teran, D. T. Hallinan Jr., A. M. Minor, A. Hexemer, N. P. Balsara, J. Electrochem. Soc., 2012, 159, A222–A227.
[ii] Y.-C. Jung, S.-M. Lee, J.-H. Choi, S. S. Jang and D.-W. Kim, J. Electrochem. Soc., 2015, 162, A704–A710.
Influence of Used Carbons and Binders on Electrochemical Properties of Li-S Cathode
Authors: Kazda Tomáš , Sedlarikova Marie , Tichý Jiří , Cudek Pavel , Fafilek Günter 
Published: February 2020

Lithium ion batteries play an important and indispensable role in the current technology thanks to the development of wearable electronics and also thanks to the increasing interest in electric vehicles. It will be necessary to replace the currently used electrode materials with new materials with higher capacity and energy density for further development in these areas, such as high-voltage batteries, lithium-sulphur batteries or Li-Air batteries. Lithium-sulphur batteries are very promising due to their high capacity and easy availability of materials. The theoretical capacity of sulphur is 1675 mAh/g and energy density is higher than 3200 Wh/kg. This system suffers by many problems. There is almost 80 % volumetric expansion during cycling on cathode or shuttle effect. Shuttle effect is probably the biggest problem of this system. Formation of polysulfides (Li2S8, Li2S6, Li2S4 etc.) takes place during charging and discharging. These polysulfides are soluble in the electrolyte and they are subsequently deposited on the anode. This process leads to the decrease of capacity and cycle life of the battery. There are many ways how to prevent this process as encapsulation of sulphur in carbon in the case of formation of the barriers on the surface of electrode or separator. Another possibility is using 3D structured cathodes. These 3D structures can keep polysulfides inside the electrode and prevent capacity decrease during cycling. A biological material with high porosity was used in this article to create a 3D structure into which sulphur was incorporated by different methods as coating or precipitation. These electrodes were cycled at various loads and compared with a standard electrode. 3D electrodes show higher stability than standard electrode and higher area capacity of more than 2 mAh/cm2.
This research has been carried out in the Centre for Research and Utilization of Renewable Energy (CVVOZE). Authors gratefully acknowledge the financial support from the Ministry of Education, Youth and Sports of the Czech Republic under NPU I programme (project No. LO1210), BUT specific research programme (project No. FEKT-S-14-2293) and in part financially supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601).
Electronic Structure Changes As Source of Chemical and Interfacial Instability in LiCoPO4 As Positive Electrode for High Voltage Li-Ion Batteries
Authors: Lapping Jacob Grant , Allen Jan L. , Jow T. Richard , Allen Joshua L. , Johannes Michelle , Freeland John W , Cabana Jordi 
Published: February 2020

The energy storage capability of a battery scales with the potential difference between its electrodes. Yet operation of positive electrode materials at high potentials introduces challenges of stabilization of charged states. As of today, no positive electrode material has been demonstrated to durably and safely operate above 4.5 V vs. Li+/Li0. LiCoPO4-based electrodes theoretically offer high specific capacity and high potentials of operation, around 4.8V vs. Li+/Li0, but these electrodes are prone to failure during cycling. Failure occurs through chemical and structural degradation in the bulk of the active material or at its interfaces with cell components, especially the electrolyte. The development of Li-ion battery electrodes operating at high potential is indispensable to meet the specific energy target of 250 kWh/kg at the packaged cell level.
Changes in the electronic structure and chemical stability of olivine-type LiCoPO4 and Fe-substituted LiCoPO4 were explored as both a function of ion substitution and oxidation state. Soft Ex situX-Ray absorption spectroscopy (XAS) made it possible to compare the changes in chemical bonding between electrode bulk and surface as a function of lithium content. This technique can probe the density of states at the transition metal and O levels. The evolution of these levels revealed changes in the metal-oxide covalence when lithium was deintercalated from the structure, and, thus, the material was oxidized. An increase in covalence can lead to the destabilization of the anions. If this process takes place in the bulk of the material, this destabilization can lead to thermal degradation via oxygen loss. At the surface, even small degrees of destabilization are sufficient to produce oxidizing species that attack the electron-rich solvent molecules in the electrolyte, leading to irreversible capacity loss.
Increased metal-oxygen covalence was universally observed in the spectroscopy in the form of a rising pre-O K-edge peak at ~530 eV as a function of lithium deintercalation in both bulk and surface. However, accompanying changes in the Co spectroscopy were only observed in the Fe-substituted sample. These changes are also indicative of increased hybridization between Co 3d and O 2p orbitals. Co K-edge XANES and EXAFS experiments further corroborated these findings, in which virtually no changes in the Co K-edge were observed upon oxidation of unsubstituted LiCoPO4. Fe doping appears to play a substantial role in getting Co to participate in redox chemistry, and the mechanism by which it occurs is currently being explored using Density Functional Theory. Fe-substituted LiCoPO4 is an exciting new positive electrode material that may prove useful in advancing Li-ion battery technology.
A123's High Power and High Energy Li-Ion Chemistry Development for Vehicle Electrification
Authors: Johnson Derek C , Hammoud Maha , Xu Charlie , Wang Jun , Campion Christopher , Iocco Rocco 
Published: February 2020

A123 has traditionally been a lithium-ion phosphate (LFP) focused company, providing state-of-the-art, high power solutions with excellent safety for low voltage automotive applications. This focus continues to result in the development of unique LFP synthesis and crystal structure doping processes to further enhance low temperature performance. In an effort to produce safe, high-energy density cells utilizing nickel-rich NCM cathodes and large capacity anode materials, A123 is implementing the same crystal level doping and surface coating approach that has been effective for low voltage material development. This presentation topic is therefore focused on the high power cathode material development that has resulted in Lithium Ion Starter Batteries (LiSBs) with cold crank capabilities that surpass lead acid batteries and high energy advancements at the material and cell levels in order to achieve energy densities approaching 300 Wh/kg and 600 Wh/L for EV applications.
Stabilizing the Solid Electrolyte Interphase on Silicon-Based Anode Materials for Lithium-Ion Batteries By in-Situ Reductive Electropolymerization
Authors: Moeremans Boaz , Zheng Yueming , Duarte Roberto Felix , Deduytsche Davy , Detavernier Christophe , Hahlin Maria , Boyen Hans-Gerd , Hardy An , Van Bael Marlies K , Renner Frank Uwe 
Published: February 2020

Increasing the capacity of Li-ion batteries and making the involved interfaces much more stable is one of the crucial current challenges for sustainable energy use.1 Silicon anodes promise almost a 10-fold capacity increase with respect to conventional graphite anodes.2 The continuous degradation of the Solid Electrolyte Interphase (SEI) at the surface of silicon-based anode materials has been recognized as the key problem of these electrodes, currently preventing their commercial introduction.3 The effect of the addition of additives to the electrolyte has been investigated in the past on graphite anodes, resulting in the use of FEC and VC in commercial lithium-ion batteries. However, due to the severe volume expansion of silicon during battery cycling, the SEI is under much higher stresses compared to graphite. Hence the stabilization of the SEI on silicon is required to improve its battery performance.
Here we present a methodology to specifically introduce polymer species into the SEI. We analyzed the interfacial film using Hard X-ray Photoelectron Spectroscopy (HAXPES), Raman spectroscopy and electrochemical testing. HAXPES enabled us to address the full depth-dependent layer chemistry and allowed us to probe the interface of the solid-electrolyte interphase and the silicon-based electrode. Figure 1a shows the C1s spectrum of the SEI on a silicon based anode after cycling using a standard electrolyte and for Figure 1b an electrolyte with the monomer additive. A detailed analysis gives information on the SEI layer thickness and the distribution of the additive-based polymer formation. In particular Br2p3/2 HAXPES spectra reveal more details on the mechanism. The battery performance of the additives was investigated by coin-cell battery testing and provides a more detailed view into the influence of electrolyte additives on the SEI.
REFERENCES
1. J. B. Goodenough and K.-S. Park, J. Am. Chem. Soc.
135, 1167-1176 (2013).
2. M. N. Obravac and L. Christensen, Electrochemical and Solid-State Letters
7, A93-A96 (2004).
3. B. Philippe, K. Edström et al., Chemistry of Materials
24, 1107-1115 (2012).

Figure 1
Unusual Na Storage Behavior of Ordered Mesoporous Carbon on Ether-Based Electrolyte System
Authors: Kim Yunok , Jeong Mihee , Lew Gil Hwan , Oh Woong , Jin Xing , Kim JI Man , Yoon Won-Sub 
Published: February 2020

The Li-ion battery (LIB) market increases rapidly due to the development of portable electronic devices and energy storage systems (ESSs). By increasing the demand for commercialization of scale-up LIB, large amounts of accumulated lithium resources will be consumed in the near future. Recently, Na-ion battery (NIB) system is considered as an alternative to LIB system because sodium resources are abundant and distributed around the world as well as sodium storage mechanism is similar to that of lithium. In contrast to LIB, graphite is not suitable for NIB anode material due to the small interlayer for large ionic radius of Na+ ion. Therefore, previous studies have investigated that non-graphitic carbon materials can deliver reversible Na+ ion insertion and extraction with initial capacity up to 300mAh g-1, however, the cycle stability of non-graphitic carbon materials is very poor.
Ordered mesoporous carbon (OMC) has the advantage of large surface area due to the development of nano-sized pores inside a micron-sized particle, which results in large electrode/electrolyte interface, easy penetration of electrolyte, and fast diffusion of Li+/Na+ ion. The ordered hexagonal structure of the OMC was formed as an inverse replica of a mesoporous silica SBA-15 structure and started from phenanthrene as a carbon source. In carbonate-based electrolyte system, the first and second discharge capacities of the OMC were 800 mAh g-1 and 350 mAh g-1 at a current density of 100 mA g-1, respectively, which means a large irreversible capacity loss, whereas in ether-based electrolyte system, the first irreversible capacity decreased considerably, implying an enhanced reaction reversibility. Even though the first discharge capacity in the ether-based electrolyte was about 200 mAh g-1, the capacity in the ether-based electrolyte increased during repeated cycling and achieved 350 mAh g-1 after 100 cycles. In contrast, the cycle retention in carbonate-based electrolyte degraded down to 200mAh g-1 consistently during 100 cycles.
To elucidate the electrolyte system-dependent Na+ storage of the OMC, various electrochemical analyses and synchrotron X-ray based techniques were performed using two-type electrolytes of 1 M NaPF6 in EC/DMC=1/1 and 1 M NaPF6 in DEG/DME.
Scalable modified Solid-State Synthesis of Na2Ti3O7 Nanorods As Anodes for Sodium-Ion Batteries
Authors: Li Chi-Ying Vanessa , Ho Ching-Kit , Chan Kwong-Yu 
Published: February 2020

Sodium-ion batteries are regarded as one of the potential candidates to substitute lithium ion batteries in large-scale electric energy storage applications in the near future. [1] Several forms of sodium titanates including Na2Ti3O7, Na2Ti6O13 and Na4Ti5O12have been recently applied as anode in sodium ion batteries. [2-4]
In this study, single-crystalline Na2Ti3O7 nanorods are successfully fabricated by solid-state method with the addition of some solid additives. The electrochemical performance of Na2Ti3O7 nanorods is compared to conventionally synthesized Na2Ti3O7 irregular particles. Na2Ti3O7 nanorods outperform Na2Ti3O7 irregular particles at all current rates in the range of 0.1 to 5 C. Without surface modification, the nanorods can still manifest a reversible discharge capacity of 70 mAhg-1at a high current rate of 5 C. The enhanced electrochemical performance can be attributed to the high surface area of the nanorods as well as efficient ion transport induced in highly uniform one-dimensional nanostructure.

References

H. Pan, Y.-S. Hu and L. Chen, Energy & Environmental Science, 2013, 6, 2338-2360.

P. Senguttuvan, G. Rousse, V. Seznec, J.-M. Tarascon and M. R. Palacín, Chemistry of Materials, 2011, 23, 4109-4111.

A. Rudola, K. Saravanan, S. Devaraj, H. Gong and P. Balaya, Chemical Communications, 2013, 49, 7451-7453.

P. J. P. Naeyaert, M. Avdeev, N. Sharma, H. B. Yahia and C. D. Ling, Chemistry of Materials, 2014, 26, 7067-7072.

Acknowledgements

This project is financially supported by Research Grants Council of Hong Kong (GRF 17300014), HKU Small Project Funding (201409176115), HKU Strategic Research Theme on Clean Energy, and University Development Fund for Initiative for Clean Energy and Environment.

Figure 1
Development of Thin-Film Solid Electrolyte-Electrode System for All-Solid-State Application
Authors: Frech Florian , Lorrmann Henning , Sextl Gerhard 
Published: February 2020

All-solid-state batteries have been shown as an innovative candidate for next-gen lithium-ion batteries. Thin-film technologies offer an approach to solve several inherent challenges. To achieve a complete thin-film all-solid-state battery all components, especially electrodes and solid electrolytes have to be prepared in a suitable combination. In contrast to conventional liquid-solid electrolyte-electrode systems, additional requirements arise from the fact that electrochemically active interfaces have to be formed while preparing.
Using cost efficient and upscalable sol-gel processes solid NASICON-type electrolytes (e. g. Li1+xAlxTi2-x(PO4)3, LATP) offer a high ionic conductivity at room temperature and a high anodic stability [1]. In previous work we presented a LATP solid electrolyte prepared by sol-gel methods on a current collector as substrate [2]. In a layer-by-layer setup (shown in Fig. 1) the substrate-anode system forms the underlying substrate for the electrolyte coating. Oxide-based electrodes indicate interfacial reactions in the presence of NASICON-type electrolytes at temperatures higher than 300 °C [3]. Therefore they turned out to be unstable in the coating-associated temperature treatment. Phosphate-based electrode materials provide a suitable approach.
This poster presents single- and multi-layer films a of phosphate-based anode material on conducting transparent oxides prepared by dip- and spin- coating method. The single- and multi-layer systems exhibited good electrochemical properties and appear suitable for the electrolyte coating process including the associated temperature treatment. Grazing incidence X-ray diffraction reveals no interface reaction and SEM investigation shows a good physical connection on the electrolyte-electrode interface. Furthermore, half-cell CV and cycling tests confirm a low charge transfer resistance at the interface. Future work will focus on the cathode/electrolyte interface and finally a working solid-state cell.
[1] P. Knauth, Solid State Ionics
2009, 180, 911–916.
[2] F. Frech et. al., Development of thin glass-ceramic electrolytes via a sol-gel route, Poster on IMLB 2014
[3] A. Aboulaich et. al., Adv. Energy Mater.
2011, 1, 179–183

Figure 1
Has the Recycling of Lithium Ion Batteries Raw Materials Become Necessary?
Authors: Lifton Jack P 
Published: February 2020

The total supply chain for the production of lithium ion batteries critically involves recycling, because either there isn't enough production of lithium, cobalt, and titanium or the supplies of them are geopolitically constrained or limited. The world base metal commodity glut has simultaneously slowed or stopped the production of the technology metals and materials necessary to produce lithium ion batteries. In fact without additonal or new supplies from existing mines the production of lithium ion batteries may need to be slowed and matched to the recycling of the critical materials. Finally the recycling of lithium ion batteries to recover the raw materials used in their construction is itself a step in more than one supply chain. Corodination among the separate supply chains for lithium salts; battery grade graphite; cobalt; and titanium will also be necessary. Has American industry recognized this problem? Even if so, can solutions be implemented in time to support the rapid build up of the electric vehicle ramp up now under way?
Identifying the Origin of Stability of Cathode Materials with Al3+-Based Surface Modifications: Amorphous Al2O3 or Crystalline LiAlxCo1-XO2?
Authors: Hu Linhua , Phillips Patrick J , Key Baris , Cabana Jordi 
Published: February 2020

Chemical degradation at electrode/electrolyte interfaces in Li-ion batteries creates the challenge of designing stable cathode materials to avoid the loss of active cathode material at the interface of the cathode and electrolyte. Surface modification with non-active oxide is regarded as a valid strategy to decrease such degradation based on their role as electronic insulator between cathode and electrolyte. Although different oxides have been reported to enhance stability against chemical degradation, the realization of stability and durability of surface modified cathode materials is not well understood owing to the inhomogeneity and complex morphology of typical cathode powders and the resulting difficulty in properly characterizing the surface structure. Indeed, the specific chemical identity of the non-active oxide on the surface of cathode materials can vary. For instance, Al3+ can incorporate as amorphous Al2O3 or crystalline LiAlxCo1-xO2, among others.

Herein, we directly synthesized well-defined LiCoO2 (LCO) nanocrystals with a hydrothermal process and employed as model cathode materials before coating 2nm uniform Al3+ oxide thin films on their surface and annealed at different temperatures. Phase analysis have confirmed that Al can be formed as Al2O3 at low temperature and as LiAlxCo1-xO2 at high temperature. Microscopy analysis presents direct proof of Al conformally coated on their surface. The electrochemical properties have demonstrated the different effect of coating with different Al-containing phases. Compared to bare LCO nanoplates, amorphous Al2O3 film coated on such nanoplates presents higher capacity and average stability whereas LiAlxCo1-xO2 coated film have much higher stability with average capacity. Data from atomic resolution TEM and solid state NMR will be discussed.