bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro-Raman Characterization of Single Particles for Phase Transformations Study in Lithium Titanate
Authors: Slautin Boris N. , Gorshkov Vadim S. , Kuznetsov Dmitrii K. , Zelenovskiy Pavel S. , Alikin Denis O. , Kiselyov Eugene A. , Kholkin Andrei L. , Shur Vladimir Ya. , Pelegov Dmitry V. 
Published: February 2020

Fast growth of battery market driven by electric vehicle (EV) and stationary energy storage system (ESS) segments has stimulated interest for lithium titanate Li4Ti5O12 (LTO) with its low cost, perfect cycleability and excellent safety. Whereas low electric conductivity (10-8 ÷ 10–13S/cm) is a weak point of LTO, it can be compensated by the grain size reducing down to sub-micron even nano scales. In spite of modern level of nanotechnology development, the structural characterization is still mainly made by non-local methods. In this work we demonstrate that structural heterogeneity in commercial negative electrode material LTO with sub-micron grain size synthesized using standard solid-state method can be described not only thermodynamically, but also locally in terms of structural characterization of single particles using standard micro-Raman Spectroscopy together with Scanning Electron Microscopy.
Solid state synthesis of Li4Ti5O12 was made using chemically pure titanium dioxide TiO2 (anatase) and chemically pure lithium carbonate Li2CO3by the following reaction:
2Li2CO3 + 5TiO2 = Li4Ti5O12 + 2CO2↑ (1)
Our modification of usual solid-state method, based both on analysis of intermediate reactions and review of the published data, uses three consequent synthesis stages with intermediate grinding which increased influence surface layers on material physical properties. In order to simplify other phases observation we knowingly increased the content of phase diagram nearest compositions TiO2 и Li2TO3by using partial (incomplete) synthesis with skipped third stage.
Raman spectra of single particle (Figure 1) clearly demonstrate heterogeneity of phase transformations during reaction (1) and allow making us some conclusions about the processes peculiarities which can’t be made otherwise.
Figure 1: SEM images and corresponding Raman spectra of single particles of (b) final phase Li4Ti5O12 and two nearest phases: (a) Li2TiO3 and (c) TiO2 rutile. SEM images sizes are 0.8×1.0 µm.

Figure 1
An Equivalent Circuit Model for Electrochemical Systems
Authors: Yamada Hidenori , Bandaru Prabhakar R 
Published: February 2020

Our recent work on modeling electrochemical (EC) energy storage devices has indicated more clearly the similarities and differences between ultracapacitors and batteries. In addition, the introduction of nanostructures into such EC storage devices introduces new physics based on the consideration of the density of states (DoS), especially in the form of quantum capacitance CQ [1]. Here, we propose an equivalent circuit model which describes EC storage deploying either traditional three-dimensional electrodes or lower-dimensional electrodes. The circuit has two separate branches: the ultracapacitor branch which involves the device double-layer capacitance and CQ (the latter being chiefly for low DoS electrodes), and a battery related branch which was modeled through diode-like characteristics with the diode characteristic of charging and discharging current in response to overpotential. It will be shown how the equivalent circuit closely models and agrees with experimental data on carbon nanotube based electrodes [1], and details related to the model validation will be discussed. The proposed equivalent circuit would explain, for the first time, the intrinsic capacitor-like and battery-like characteristics of any EC device in a unified manner.
[1] H. Yamada and P. R. Bandaru, Appl. Phys. Lett. 102, 173113 (2013), ibid 104, 213901 (2014).
Li2ZrO3 -Coated Li1.2Ni0.2Mn0.8O2 for the High Performance Cathode Material in Lithium Ion Batteries
Authors: Noh Hana , Lee Yongho , Kim Hyeongwoo , Choi Wonchang 
Published: February 2020

Introduction

Recently, high energy density lithium ion batteries (LIBs) play an important role in the field of portable and electronic devices and electrical vehicles. Although conventional layered LiCoO2 cathode material has good electrical properties, the capacity of current LiCoO2 is around 160 mAhg-1 with lithium utilization in the structure less than 50%. Moreover, their cost and safety requirement are still problems for the adoption of lithium ion technology for these large-battery application. In this reasons, during the past two decades, several cathode materials have been emerged as an alternative layered structure compounds, such as olivine phosphates (LiMPO4; M = Fe, Co, Ni, and Mn) and spinel oxides (LiM2O4; M = Mn, Ni and Co), however these still have a relatively low capacity. To overcome this problem, Over-lithiated Layered Oxide (OLO) materials have been considered one of the promising cathode materials for the next generation of cathode materials. Among them, 0.5Li2MnO3·0.5LiNi0.5Mn0.5O2 which is known as high capability (250 mAhg-1) has excellent electrochemical performance and stability at higher cut-off voltage beyond 4.8 V. However, its severe capacity fading during high current rates is generally related to the unstable structure and the side reaction with electrolytes cause problems while cathode carries out beyond 4.8 in a range of high voltage. Herein, we reports Li2ZrO3 -coated Li1.2Ni0.2Mn0.8O2 for high performance cathode material in lithium ion batteries. The concept is both to decrease the interface resistance by crystallization of the surface layer and cover the particles with Li2ZrO3that would suppress the particles against side reactions with the electrolyte. In addition, it can circumvent the loss of transition-metal ions of oxygen, without changing the electronic and ionic conductivities. In this study, X-ray diffraction, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy, Electrochemical Impedance Spectroscopy and various Charge-discharge measurements were also performed to further investigate the effect of surface-coating layer.

Experimental

To make samples, OLO was made by adding Zirconium isopropoxide was added in the mixed powder and then mixed by hand. After pelletizing, it was put in Alumina crucible and calcinated in 900 °C for 10 hours (heating rate is 5 °C/min). After calcination, powder was filtered using D.I water to remove the residue of LiOH. Resulting powder was dried at 60oC (overnight). Electrode slurry has been made of 92% of cathode materials, 4% of Denka black, 4% of PVdF. The slurry was casted on the Al foil for current collector and assembled with 2032 coin cell.

Result and discussion

Surface modification of cathode electrodes with lithium zirconia oxide gives rise to the better rate properties than pristine OLO.

Figure 1
Wide Temperature Range Electrolyte Formulations for Start-Stop Vehicle Applications
Authors: Cheng Gang , Zhu Ye , Strand Dee 
Published: February 2020

Over the last decade, many governments have implemented more stringent regulations on vehicle fuel economy and CO2 emissions. For example, European targets for new passenger cars reduce emissions to 130g CO2 per kilometer by 2015, with further reduction to 95g by 2021. Start-stop vehicle engines, which shut off during stops for traffic or at a light, play an important role in achieving these targets. These vehicles require a battery with sufficient power to re-start the engine over a wide range of conditions and sufficient energy to run the lights, air conditioning, etc. on the vehicle when stopped.
Lithium ion batteries are promising candidates to replace currently used lead acid batteries due to their high energy density as well as longer cycle life. However, the power performance of lithium ion batteries is limited at low temperatures required for automotive applications due to low conductivities of the electrolyte and the solid electrolyte interphase (SEI). Solutions to the low temperature problem generally consist of adding solvents with very low melting points and/or low viscosity to the formulation which keep the formulation from freezing or reduce the viscosity at low temperature. However, these solvents tend to be detrimental to high temperature stability, required to meet the lifetime requirements of the vehicle batteries.
Wildcat has developed electrolyte formulations that improve the power performance at low temperature, but improve or maintain the high temperature stability relative to baseline electrolyte formulation. Wide temperature range formulations were developed for both NMC//graphite and NMC//LTO electrode chemistries.
A Soluble-Lead-Redox-Flow-Battery with Embedded Reticulated Vitreous Carbon and Inter - Digitated Graphite As Negative and Positive Plates
Authors: Ravikumar Musuwathi Krishnamoorthy , Shukla Ashok Kumar 
Published: February 2020

Characteristics of a 12 V soluble-lead redox flow battery (SLRFB) stack developed by employing reticulated vitreous carbon foam embedded into graphite plate as negative flow fields and inter-digitated graphite plates as positive flow fields. The stack consists of 8 cells in series assembled with 7 bipolar plates, two monopolar plates and 8 spacers placed between each cell. The flow battery exhibits compelling Faradaic and voltage efficiencies at low current densities between 10 – 20 mAcm-2, and at charging-periods of 15-30 min. SLRFB exhibits an energy storage capacity of 50 – 60Wh and is able to deliver 100 W of constant power. Long periods of constant – current charging and higher current charging lead to a decrease in overall efficiency of the flow cell. The faradaic efficiency of SLRFB is 85% when it is charged for 15 min at 1A and is 65% when the charged for 3h. The faradaic efficiency decreases to 60% when the SLRFB is charged at 5A for 15 min. Long periods of constant current charge and discharge cycling lead to the accumulation of active materials specifically Pb and shedding of PbO2. A novel design to mitigate the aforesaid issues is highlighted and cycle – life data are presented.
Real-Time Crossover Measurement in All-Vanadium Redox Flow Batteries
Authors: Ashraf Gandomi Yasser , Aaron Douglas , Mench Matthew M. 
Published: February 2020

Redox flow batteries have emerged as one of the most promising technologies for grid-scale energy storage options. Different chemistries have been developed, including the all-vanadium redox flow battery1. Among the different components of the all-vanadium redox flow batteries, the ion-exchange membrane plays a significant role via directly affecting the voltage and coulombic efficiencies. The ideal membrane must minimize resistance for proton flux and at the same time limit unwanted crossover of active species.
The species transport mechanism through the ion-exchange membrane has been the focus of several studies 2, 3. Also, different mathematical models have been developed to predict the transport through the membrane 4-8. However, experimental studies for the species transport through the ion-exchange membrane is rare 9, 10. In this talk, we will report on results of direct species crossover measurement through the ion-exchange membrane for the all-vanadium redox flow batteries. A unique test facility utilizing several test cells and UV-Vis spectrometry has been designed and verified that enables measurement of the species crossover with and without electric fields, so that individual driving forces of transport can be deconvoluted. The experimental data reveals the different crossover rates for individual vanadium oxide species as a function of concentration and electric field effect.
1. M. Skyllas-Kazacos, M. Chakrabarti, S. Hajimolana, F. Mjalli, and M. Saleem, Journal of the Electrochemical Society, 158 (8), R55-R79 (2011).
2. A. Z. Weber and J. Newman, Journal of the Electrochemical Society, 150 (7), A1008-A1015 (2003).
3. Y. A. Gandomi and M. M. Mench, ECS Transactions, 58 (1), 1375-1382 (2013).
4. A. Z. Weber and J. Newman, Journal of the Electrochemical Society, 151 (2), A311-A325 (2004).
5. K. Knehr, E. Agar, C. Dennison, A. Kalidindi, and E. Kumbur, Journal of The Electrochemical Society, 159 (9), A1446-A1459 (2012).
6. R. Darling, K. Gallagher, W. Xie, L. Su, and F. Brushett, Journal of The Electrochemical Society, 163 (1), A5029-A5040 (2016).
7. Y. A. Gandomi, D. Aaron, T. Zawodzinski, and M. Mench, Journal of The Electrochemical Society, 163 (1), A5188-A5201 (2016).
8. Y. A. Gandomi, T. A. Zawodzinski, and M. M. Mench, ECS Transactions, 61 (13), 23-32 (2014).
9. C. Sun, J. Chen, H. Zhang, X. Han, and Q. Luo, Journal of Power Sources, 195 (3), 890-897 (2010).
10. Q. Luo, L. Li, Z. Nie, W. Wang, X. Wei, B. Li, B. Chen, and Z. Yang, Journal of Power Sources, 218 15-20 (2012).

Figure 1
Chemically Functionalized Graphene for High Performance Lithium/Sulfur Batteries
Authors: Zhang Yuegang 
Published: February 2020

Carbon is an indispensible material for electrochemical energy storage applications. Graphene, with its high conductivity, high surface area, and high mechanical strength, has emerged as a magic material in the electrodes of the most advanced supercapacitors and lithium batteries. In this talk, I will demonstrate that graphene, with proper chemical functionalization, could play an important role in improving the lithium/sulfur cell’s active material utilization, specific capacity, as well as its cycle life. Using a nitrogen-functionalized graphene–sulfur electrode, we have achieved ultra-stable cycling exceeding 2000 cycles with a capacity decay rate as low as 0.028% per cycle. To understand the underlying mechanism of the electrochemical reaction processes, we developed various in-situ experimental tools so that we can conduct real time TEM and SEM Raman investigation during electrochemical measurements. Based on these in-situ and other ex-situ characterization results, we develop a way to prevent lithium dendrite formation by using an optimized electrolyte and to minimize sulfur loss through the chemical interactions of the functional groups on graphene with the active electrode material, i.e. sulfur or lithium sulfide, as well as with the intermediate lithium polysulfide products.
VO2 Nanoplatelets: A High Energy Electrode Material for Lithium Ion-Hybrid Electrochemical Capacitors
Authors: Satish Rohit , Vanchiappan Aravindan , Wong Chui Ling , Srinivasan Madhavi 
Published: February 2020

Lithium ion hybrid capacitors (LIC) is an energy storage solution that combines the best of both worlds in terms of high power and high energy density. One of the participating electrodes stores charge by a faradaic mechanism (battery) while the other electrode stores charge by the formation of an electrical double layer (supercapacitor). This configuration allows for the exploitation of the niche gap between batteries and supercapacitors, allowing for the development of a possible energy storage solution for Plug in hybrid vehicles with fast charging and long range capabilities.
Vanadium dioxide has recently received much attention because of their high capacity when compared to other vanadium analogues. It consists of sheets of VO6 octahedras linked with each other at the corner, the layered structure allows for good lithium kinetics. The high capacity of Vanadium dioxide even at high power loads is postulated to mitigate one of the main issues faced by LIC’s, that the power density of the device is limited by the battery electrode and most battery electrodes tend to fail at high power loads.
Vanadium Dioxide nano-platelets were synthesized using a mechanically assisted hydrothermal reaction. The material was characterized using X-ray diffraction to check for phase purity, scanning electron microscopy and high resolution tunneling electron microscopy were used to characterize the effects of agitation on the morphology of the sample. The morphology is then co-related to the electrochemical performance of the material to develop an understanding about the effect of mechanical agitation on cell performance.
Comprehensive electrochemical studies were performed on both VO2 and commercial Activated carbon (acts as the supercapacitor electrode) to determine the mass loading in a full cell arrangement. Half cell studies on VO2 were conducted between 2-3 V vs. Li a high capacity of ~250 mAh g-1 was recorded with barely any capacity drop at high current rates. Because of the robustness of VO2 during high current operations it can be applied in applications that require to store a large amount of energy and at the same time be able to undergo fast charge discharge cycles.
Investigating the Role of Transition Metal Deposition on Solid Electrolyte Interphase Formation and Growth Using Redox Shuttles
Authors: Jaini Rajiv , Fuller Thomas F 
Published: February 2020

Transition metal based electrodes are attractive positive electrode materials for lithium ion-batteries due to their high energy densities and large capacities. However, these positive electrode materials are prone to dissolution of the transition metal structure into the electrolyte. The subsequent result of the dissolution is accelerated capacity and power fade. Investigation into the dissolution phenomena shows that after dissolution, the transition metals transport to the negative electrode. It is there where the metals ions deposit on the negative electrode surface, catalyzing solid electrolyte interphase (SEI) growth and blocking active sites for intercalation (1-3). In spite of these studies, much remains unclear about variations in the morphology and electronic passivity of the SEI due to transition metal deposition on the negative electrode surface.
In this work, we investigate changes in the morphology and electronic passivity of the SEI using redox shuttles. We introduce manganese, nickel, and cobalt-based transition metal salts over a range of concentrations to the primary electrolyte. SEIs are formed on glassy-carbon electrodes by applying potentiostatic holds and cyclic voltammetry (CV). After formation, the SEI is probed using the ferrocenium-ferrocene redox shuttle. A mathematical model of the electrode-electrolyte interface is used to quantify the thickness and porosities of formed SEIs.
Figure 1(a) shows the effectiveness of the redox shuttle in characterizing the magnitude of passivation on the working electrode surface. The working electrode is glassy carbon and primary electrolyte is (1:1 wt%) ethylene carbonate : diethyl carbonate with 1 M LiPF6 salt. CVs were measured at ν = 10 mV s-1 around the equilibrium

redox potential, ~ 3.24 VLi/Li
+. Increasing passivation time reduces redox peak currents, suggesting that surface passivation limits redox kinetics. Figure 1(b) shows experimentally obtained and simulated CVs, demonstrating that the system can be effectively modeled with an SEI.
References
1. T. Joshi, K. Eom, G. Yushin and T. F. Fuller, Journal of the Electrochemical Society, 161, A1915 (2014).
2. C. Delacourt, A. Kwong, X. Liu, R. Qiao, W. L. Yang, P. Lu, S. J. Harris and V. Srinivasan, Journal of the Electrochemical Society, 160, A1099 (2013).
3. J. Lu, C. Zhan, T. Wu, J. Wen, Y. Lei, A. J. Kropf, H. Wu, D. J. Miller, J. W. Elam, Y.-K. Sun, X. Qiu and K. Amine, Nat Commun, 5 (2014).

Figure 1
Transition Metal Sulfide Based Cathode Materials for Efficient Hybrid Supercapacitors
Authors: Chen Yin-Ying , Chou Shu-Wei , Lin Jeng-Yu 
Published: February 2020

Supercapacitors (SCs) have been widely recognized in a wide range of energy storage applications over the past decade, such as hybrid electric vehicles, mobile electronic devices, large industrial equipments, memory backup systems, and military devices, due to their unique properties including higher specific power density (10 kW kg-1) than batteries, and higher specific energy density (5-10Wh kg-1) than conventional dielectric capacitors without sacrificing cycle life (>100,000 cycles). In recent years, nanostructured metal sulfides have been intensively investigated as SCs electroactive materials.
In this study, nickel and cobalt binary sulfide nanoparticles decorated on the surface of multi-walled carbon nanotubes (designated as Ni-CoS/MWCNT composite) and Ni3S2 thin films directly deposited onto Ni foam is successfully prepared by a facile glucose-assisted hydrothermal method and pulse-reversal (PR) deposition approach. On the basis of tuning the Ni/Co molar ratio of the Ni-CoS/MWCNT composites, the optimized Ni-CoS/MWCNT composite was employed as the cathode and a reduced graphene oxide was used as the anode to fabricate a hybrid supercapacitor (HSC). As-fabricated HCS is able to be operated reversibly in a full voltage region of 0–1.6 V and achieves a high specific capacity of 33 mAh g−1 at 1 A g−1. Moreover, it can still deliver a maximum energy density of 23 Wh kg−1 at a power density of 684 W kg−1. Furthermore, the HSC still retains 90% of its initial discharge capacity after 2000-cycle charge/discharge test at a fair high current density of 4 A g−1. Additionally, another HSC is then assembled by using the optimized PR-Ni3S2 electrode as cathode and carbon fiber cloth (CFC) as anode, respectively. The HSCs can be operated with a potential window between 0 and 1.8 V and deliver a high specific capacity value of 25.5 mAh g-1 at 0.5 A g-1. Moreover, the energy density and power density of the HCS can be achieved up to 28.8 Wh kg-1and 564 W kg-1, respectively. The most important thing is that the HSC displays excellent cycling stability with only 20% capacity loss after 5000 cycles. As a result, the highly efficient HSCs can be achieved based on the transition metal sulfide based materials as cathodes
Lithium-Ion Capacitor Based on Electrodes Constructed Via Electrochemical Spray Deposition
Authors: Agrawal Richa , Wang Chunlei 
Published: February 2020

Conventional Electrochemical double-layer capacitors (EDLCs) are well suited as power devices that can provide large bursts of energy in short time periods. However, their relatively poor energy densities hinder their application in devices that require simultaneous supplies of both high energy and high power. In the wake of addressing this shortcoming of EDLCs, the concept of hybridization of lithium-ion batteries (LIBs) and EDLCs has started to gain popularity in recent years. Such a device, generally referred to as the “lithium-ion capacitor” typically utilizes a lithium intercalating electrode along with a fast charging capacitor electrode in a lithium-containing electrolyte. Herein we have constructed a lithium ion capacitor comprising a Li4Ti5O12 (LTO) anode and a graphene and carbon nanotube (G-CNT) composite cathode using electrostatic spray deposition (ESD). The morphology and material properties were studied scanning electron microscopy and X-ray diffraction studies, respectively. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy measurements were carried out to evaluate the electrochemical performance of both half cells and full cells. The details will be presented at the conference.
Performance Evaluation of Intermediate-Temperature Reversible Solid Oxide Fuel Cell at VPS
Authors: He Hongpeng , Wood Anthony , Joia Tahir , Krivy Mark , Steedman Dale 
Published: February 2020

Hydrogen has been considered as a potential alternative fuel for future energy supplies and can be produced through high temperature steam electrolysis. The technology can be realized through reversible operation of solid oxide fuel cells (SOFCs), involving reduction of water at the cathode to form hydrogen and rejection of oxygen to air at the anode. Versa Power Systems (VPS) is a developer of SOFC technology focused on large stack and system development for commercial applications. In recent years VPS has been developing RSOFC material systems for the purpose of future commercial development of RSOFC stacks. VPS has demonstrated significant technical improvements in RSOFC materials technology including demonstrated cell operation up to 6 A/cm2 with <1.67 V operating voltage at 800°C. Recent work has focussed on the effects of testing conditions on cell durability using performance testing (polarisation) and electrochemical impedance spectroscopy.