bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Simulation of Heat of Mixing in Lithium Ion Batteries
Authors: Song Zhibin , Yan Bo , Lim Cheolwoong , Zhu Likun 
Published: February 2020

Heat generation is a major safety concern in the design and development of lithium ion batteries (LIBs) for large scale applications, such as electric vehicles. The total heat generation in LIBs includes entropic heat, enthalpy, reaction heat, and heat of mixing (1-3). The heat of mixing will be released during relaxation of Li ion concentration gradient. For instance, after the drivers turn off their vehicles, the generation of entropy, enthalpy and reaction heat in LIBs will stop, but the heat of mixing is still being generated. Thomas and Newman derived methods to compute heat of mixing in LIB cells and investigated the heat of mixing on a Li|LiPF6 in ethylene carbonate:dimethyl carbonate|LiAl0.2Mn1.8O4-δF0.2 cell (4). The objective of this study is to investigate the influence of heat of mixing on the LIBs with different materials, porosities, particle sizes, and charge/discharge rate and to understand whether it is necessary to consider heat of mixing during the design and development of LIBs.
In this study, a mathematical model was built to simulate heat generation of LIBs using COMSOL Multiphysics. The LIB model was based on Newman’s model. LiCoO2 was applied as the cathode materials, and LiC6 was applied as the anode material. The results of heat of mixing were compared with the other heat sources to investigate the weight of heat of mixing in the total heat generation. Table 1 shows the heat of mixing, irreversible heat, and reversible heat in anode and cathode electrodes at 5 min during a 2 C discharge process. As shown in Table 1, the heat of mixing in cathode is smaller than the heat of mixing in anode, mainly due to the lower Li ion diffusivity and larger particle size of LiC6. The heat of mixing is not as much as the irreversible heat and reversible heat, but it cannot be neglected for this operating condition. The heat of mixing in different LIB cells and under different operating conditions will be reported.
The mathematical model equation(1):
Show in Image 1.
Acknowledgments: This work was supported by the American Chemical Society
Petroleum Research Fund.
Table 1. Comparison of the heat of mixing within active material particles with irreversible and reversible heat sources at 5 min during a 2 C discharge process.

Cathode(LiCoO2)
Anode(LiC6)

Heat of mixing
3.92 J/m2

293.60 J/ m2

Irreversible heat
460.97 J/m2

1354.86 J/m2

Reversible heat
1370 J/m2

-813 J/m2

References:
1. K. E. Thomas and J. Newman, Journal of the Electrochemical Society, 150, A176 (2003).
2. B. Yan, C. Lim, L. Yin and L. Zhu, Journal of the Electrochemical Society, 159, A1604 (2012).
3. K. Kumaresan, G. Sikha and R. E. White, Journal of the Electrochemical Society, 155, A164 (2008).
4. K. E. Thomas, C. Bogatu and J. Newman, Journal of the Electrochemical Society, 148, A570 (2001).

Figure 1
Novel BCC Anode Materials for High-Power Alkaline MH-Air Batteries
Authors: Tan Hongjin , Weadock Nick , Fultz Brent , Bugga Ratnakumar V 
Published: February 2020

Aqueous metal hydride air batteries (MH-Air) offer an inexpensive and safe alternative to the Li-ion batteries for electric vehicles. To be competitive with Li-ion batteries, the energy density of a metal hydride battery system can be improved by introducing a low-mass bifunctional air cathode and developing a higher capacity anode material. V-based BCC alloys are promising high-capacity anode materials, and discharge capacities of greater than 450 mAh/g have been reported for TiV2.1-xCrxNi0.3 alloys.1 V-based BCC alloys containing Ti and Ni have been shown to separate chemically into a two-phase mixture with a minority Ni-Ti phase within a V-rich matrix,2 and we report the effects of this unmixing on electrochemical properties.
The Ti-V-Cr-Ni BCC electrode materials were prepared by arc melting and rapid cooling with an Edmund Buhler compact MAM-1 with an attached suction casting crucible. The control samples were made by conventional arc melting under Ar. As-cast ingots were pulverized by hydriding in a Sievert’s apparatus. The samples were analyzed by x-ray diffractometry (XRD), scanning and transmission electron microscopy (SEM, TEM) and energy-dispersive x-ray spectrometry (EDS). The anode was prepared by pressing a mixture of alloy and Ni powders onto Ni mesh. Electrochemical cycling experiments were conducted in a half cell containing 30% aqueous KOH electrolyte, a Ni(OH)2 counter electrode and an Hg/HgO reference electrode. The electrode was charged at 100mA/g and discharged three times at 167mA/g, 50mA/g, and 10mA/g; each to a cut-off voltage of -0.7V vs. Hg/HgO.
EDS mapping showed, as expected,2 a Ti-Ni rich secondary phase in the arc melted sample that permeates the micron-scale primary V phase. (Fig. 1, top, Ni phase in green.) No phase segregation is resolved by EDS for the suction cast alloy. (Fig. 1, bottom). For the first 100 charge-discharge cycles, both materials gave similar capacities. However, at each cycle, the suction cast alloy consistently discharges with 20%-40% more capacity during the high-rate step (167mA/g, ~C/3, 1st step in Fig. 2).
It has been argued that the Ni-Ti phase is important for the electrocatalytic dissociation of H2 molecules during charge, and the matrix V-rich phase is the storage region for hydrogen.2 Reducing the length scale of the phase segregation of the Ni-Ti regions by rapid cooling may therefore improve the kinetics of the material by reducing the hydrogen diffusion length and by increasing surface area for electrocatalysis.

Inoue, et al. Electrochimica Acta, (2012), 59, 23-31.

Tsukahara, et al., J. Alloys Comp. (1997), 253-4, 583-6.

Figure 1
A Systematic Study on Sodium Doped Strontium Silicate for SOFC Application
Authors: Jee Youngseok , Xiong Xiaolei , Tong Jingjing , Si Fengzhan , Wang Jie , Fang Jie , Huang Kevin 
Published: February 2020

1. Introduction

High temperature (HT) operation at 800 – 1000 °C causes many problems such as the thermal mismatch between membrane electrode assembly (MEA) components, expensive bipolar plates, micro structural changes, inter-diffusions, slow start-up time, decreasing system power density due to heat insulators. In order to overcome this main commercialization obstacle of solid oxide fuel cells (SOFCs), a lot of intermediate temperature (IT) electrolyte materials (Doped ceria, LSGM, ScSZ and so on) which can substitute for conventional YSZ have been proposed. And various thin film deposition techniques (Screen printing, Dip-coating, Magnetron sputtering, Pulsed Laser Deposition, Chemical Vapor Deposition and Atomic Layer Deposition) were applied to this research field. The goal of both types of approaches is minimizing the ionic resistance at decreased temperature.
Recently, the sodium doped strontium silicate (Sr1-xNaxSiO3-0.5x) is gathering attentions as a fast ion conductor.[1] And Wei et al. confirmed a good SOFC performance using this electrolyte material at 500 and 600 °C. [2] In this study, we investigated on this promising material to get the optimal fabrication conditions with composition and to minimize several problems on this material.

2. Experimental

The starting raw powders of SrCO3 (Sigma-Aldrich 99.9%), Na2CO3 (Alfa Aesar, 99.9%) and SiO2(Alfa Aesar 99.9%) were mixed and ball milled. The Na doping percentages on strontium site were 0 to 100 %. We varied calcination temperature from 600 °C to 1000 °C. After ball milling step, we also varied sintering temperature (800 – 1150 °C) and time (10, 20 and 100 h).
Conductivity tests were conducted in the air environment and the furnace was controlled from 400 to 750 °C. Sample pellet was prepared to get the thickness of 1.5 mm using low speed saw. Then, we pasted silver electrodes with current collecting meshes on both sides of pellets and connected wires to electrochemical impedance spectrometer (Solartron 1287 and 1260, UK). The micro structural images were captured using a field emission scanning electron microscope (FESEM, Zeiss Ultra) equipped with an energy dispersive X-ray spectroscopy (EDS) analyzer, respectively. The phase check was done using an X-ray diffractometer (D/max-A, Rigaku, Japan) with CuKα radiation (λ=1.5418 Å). The scan range was 2θ = 10 – 70 °at a rate of 5 ° min-1.
From this study, we found out the optimal fabrication conditions (sintering at 900 °C for 10 h) for 45 % sodium doped strontium silicate electrolyte which was known as the best ionic conductor. Moreover, we could guess the origin of this high conductivity was from the amorphous sodium silicate.

Reference

[1] P. Singh and J. B. Goodenough, J. Am. Chem. Soc., 2013, 135, 10149–10154
[2] T. Wei, P.Singh, Y. Gong, J.B. Goodenough, Y. Huang and K. Huang, Energy Environ. Sci., 2014, 7, 1680-1684

Figure 1
Nanostructured Ni-YSZ Anode By Atomic Layer Deposition for Solid Oxide Fuel Cells
Authors: Cui Xiaodan , Zdunek Alan D. , Takoudis Christos G 
Published: February 2020

Nickel yttria-stabilized zirconia (Ni-YSZ) is the most commonly used anode for solid oxide fuel cells (SOFCs). The electrochemical performance of Ni-YSZ anodes can be improved when the size of constituent particles is reduced. However, under SOFC operating environment, nano-sized Ni particles suffer from sintering; nanoscale Ni-YSZ anodes can undergo structure changes, which constrain the development of nanoscale Ni-YSZ anodes.
In this work, nanoscale nanostructured Ni-YSZ anode was successfully fabricated by combining atomic layer deposition (ALD) and glancing angle deposition (GLAD). Prior to atomic layer deposition of YSZ, the porous Ni nanorod electrode was firstly prepared by GLAD. ALD was applied to deposit a uniform nanoscale YSZ coating layer over the nickel nanorods. The morphology of the nanostructured Ni-YSZ anode was examined with scanning electron microscopy (SEM). The surface area was increased to more than 3 times as large as plane area and the triple phase boundary (TPB) extended to the entire nickel surface. The surface composition was examined with X-ray photoelectron spectroscopy (XPS). The atomic composition of YSZ film was controlled by the ALD process and not affected by the post-deposition annealing process. ALD coating approach combined ionic conductive YSZ electrolyte phase with electrical conductive Ni phase flexibly and controlled the porosity of the nano-composite electrode just through deposition and post-deposition annealing process. Electrical conductivity measurements were performed using a 4-point probe method. The Ni-YSZ anodes maintained resistivity in the 10-4 cm·S-1 magnitude, which is sufficiently conductive as an SOFC anode. The ALD YSZ coating layer showed sintering-resistance on the nanostructured electrode with an as thin as 1.9 nm YSZ coating layer and excellent anode performance under SOFC operating conditions.
Electrochemical Properties of Nanocrystalline Li4Mn5O12 for Hybrid Capacitor
Authors: Man Tran Van , Huynh Nguyen Le Thanh , Le Thang Van , Phung LE My Loan 
Published: February 2020

The hybrid capacitor or asymmetric capacitor is the hybridization of electrochemical capacitor and rechargeable batteries. The device is developed by hybridization on the electrode level; therefore, it is based on a battery anode (charged by faradic reaction) and electrochemical capacitor electrode (charge stored in the electrochemical double layer) [1]. Sometimes, the name “lithium-ion” capacitor was introduce to described a device using a graphite negative electrode and activated carbon (AC) based positive electrode in combination with a Li+ containing electrolyte [2].
In such device, different types of materials have been proposed for faradic component. Lithium insertion compounds used in lithium-ion batteries have attracted a lot of interest due to high specific charge. They have been typically used in organic electrolyte but the aqueous solutions are not missing [3,4]. In this work, nanocrystalline Li4Mn5O12 was low-temperature synthesized by sol-gel method with citric acid as a chelating agent. Various initial synthesis conditions were studied such as: pH of solution, the ratio of citric acid to total metal ions, the precursor of lithium salts. The structure, morphology and electrochemical properties of materials are characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), cyclic voltammetry (CV) and galvanostatic cycling with potential limit (GCPL). The stoichiometric of formula was exactly determined by reduction-oxidation titration and flame atomic absorption spectrophotoscopy (FAAS).
The resulting materials exhibited the particles size of 50 – 100 nm. The electrochemical results showed that Li4Mn5O12 synthesized at pH = 9 and the ratio of citric acid to total metal ions 1:1 exhibited the best electrochemical capacitive performance within potential range of 0 – 1.4 V in 1M Li2SO4. A maximum specific capacitance of 20 F.g-1 during 200 cycles was obtained for hybrid capacitor for AC/Li4Mn5O12 at high discharge rate of 5 A.g-1.

Acknowledgements

The authors would like to thank Office of Naval Research Global (ONRG) for the grant N62909-13-1-N235. The authors acknowledge funding from VNU-HCM under the grants HS2013-76-01.

References

[1]. D. Cericola, Electrochimica Acta 72 (2010) A536.
[2]. O. Hatozaki, Proc. Advanced Capacitor World Summit 2008, San Diego, CA, USA, 2008.
[3]. Y.J. Hao,Y.Y. Wang, Q.Y. Lai, Z. Zhao, L.M. Chen, X.Y. Ji, Journal of Solid State Electrochemistry, 13 (2009) 905.
[4]. K. Naoi, S. Ishimoto,Y. Isobe, S. Aoyagi, Journal of Power Sources 195 (2010) 6250.
Cathodic Deposition of Metal Sulfide Nanostructures As Active Materials for High-Performance Supercapacitors
Authors: 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 due to their higher specific power density, faster charge/discharge rates and longer cycle life compared to batteries. Hydrous ruthenium oxide (RuO2) has been the most promising material with the high specific capacitance (>720 F g-1). However, the low abundance and high prices restrict the application of RuO2 in SCs. Hence, several alternatives have been proposed to be capable of the RuO2such as metal oxide and conducting polymer. In addition, nanostructured metal sulfides have been widely investigated as SCs electroactive materials. In recent years, nanostructured metal sulfides have been widely synthesized by chemical precipitation and hydrothermal. Nevertheless, the aforementioned metal sulfides still needed polymer binder, conducting agent and high pressure coating on the conductive substrate, which could contribute extra contact resistance. In this way, electrodeposition seems to be a great approach to prepare the electroactive materials on conductive substrates since the active materials can be directly growth on substrates without using any polymer binder, conducting agent and high pressure, and the weight and thickness of electroactive materials can easily controlled by adjusting the deposition conditions.
In this study, cobalt sulfide and nickel sulfide nanostructures can be directly grown on Ni foam substrate as electroactive materials for high-performance supercapacitors by simply using a facile potentiodynamic deposition method. The Ni3S2 and CoS electrodes showed a high specific capacitance as well as 717 F g−
1 at 2 A g−
1 and 1471 F g−
1 at 4 A g−
1, as shown in Fig. 1(a) and Fig.1(b). As a result, nickel sulfides and cobalt sulfides can be considered as promising electrode materials for high-performance supercapacitors.

Figure 1
Facile Fabrication of Co3O4@C@Tnas Heterojunction Composites with Enhanced Electrochemical Performance for Supercapacitors
Authors: Yu Cui-Ping , Wang Yan , Zhang Jian-Fang , Shu Xia , Cui Jie-Wu , Xie Kui , Chen Zhong , Xie Ting , Wu Yu-Cheng 
Published: February 2020

A new type of supercapacitors based on the well aligned TiO2 nanotube arrays (TNAs) modified with
amorphous carbon and Co3O4 nanoparticles was prepared in this paper. Carbon-doped TNAs (C@TNAs) were fabricated by anodic oxidation of a pure titanium sheet in an aqueous
solution containing 0.25M NH4F and 7vol% H2O directly, then followed by annealing
the prepared TNAs samples in the Ar atmosphere, with the residual ethylene glycol absorbed on the
TNAs wall during anodization as the carbon source. The C@TNAs were chosen as the 3D framework
with larger surface area, easier access for the ions in the solution as well as the highly chemical
stability, and the amorphous carbon could enhance the electric conductivity of TNAs.
Co3O4 nanoparticles with the size of less than 15 nm were synthesized via the simple process of
chemical bath deposition of cobalt acetate aqueous solution, which was as a result of the hydrolysis
of Co2+ and simultaneously heterogeneous growth of Co3O4 nanoparticles on both the outer and
inner surfaces of C@TNAs. The morphology, component and electrochemical property of
Co3O4@C@ TNAs were characterized by field emission scanning electron microscope (FESEM),
transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron
spectroscopy (XPS), cyclic voltammetry (CV) and amperometry charge and discharge (CD), respectively.
The influence of amorphous carbon on promoting electrochemical properties was discussed in this paper
through comparing the CV of Co3O4 @ TNAs and Co3O4@C@ TNAs. After doped with amorphous carbon,
a maximum specific capacitance of 689 F g-1 has been obtained in 2M KOH aqueous electrolyte at current
density of 1 A g-1 with a potential window from 0 to 0.45 V (vs. Ag/AgCl). Furthermore, the specific
capacitance retains 84 % based on the initial capacitance after 4000 cycles under high current density of
10 A g-1, revealing the excellent long term electrochemical stability of the sample even at high cycling rate.
Co3O4@C@TNAs heterostructure composites will hode promise for one of the best electrode systems for high
performance supercapacitors.
GdBaM2-xFexO6-

δ
(M = Co, Mn) Perovskite-type Oxides as SOFCs Cathodes: Influence of Ordering Effects on the Crystal Structure and Properties
Authors: Garcia-Martin Susana , Muñoz-Gil Daniel , Urones-Garrote Esteban , Avila-Brande David , Martínez de Irujo Xabier 
Published: February 2020

Perovskites of general formula A1-xA’
xM1-yM’yO3-δ (A = lanthanide atom, A’ = alkali earth atom and M, M’ = transition metal atom) are promising candidates as electrodes for solid oxide fuel cells (SOFCs) [1, 2]. Among them, A-site ordered perovskites as for instance GdBaCo2O5+δ, also called layered-type perovskites, show better electrochemical behaviour than materials with random distribution of the cations. The high oxygen mobility in these layered-type perovskites seems to be related to the A-cation ordering [3, 4].
We are studying the influence of the crystal structure, in particular of the ion ordering effects, on the electrochemical properties of doubled perovskites with composition

GdBaM2-xFexO6-
δ (M = Co, Mn). The synthesis conditions affect both the oxygen stoichiometry and cation and/or anion vacancies ordering in the crystal structure of the materials. We study the crystal structure of the compounds by Selected Area Electron Diffraction (SAED), High Resolution Transmission Electron Microscopy (HRTEM), Scanning Transmission Electron Microscopy (STEM) (High Angle Annular Dark Field HAADF-STEM and Annular Bright Field ABF-STEM) and Electron Energy-Loss Spectroscopy (EELS). The use of aberration-corrected transmission electron microscopy techniques provides atomic resolution information. We have found cation ordering (mainly associated to the A cations, although B-cation ordering has also been observed) and anion vacancies ordering in some of these perovskites. HAADF-STEM images (also called Z-contrast images) confirm the layered-type ordering of the A cations. Direct imaging of the oxygen sublattice is obtained by ABF-STEM images and the phase image of the restored exit wave, which allows location of the oxygen vacancies in the structure.
We study the electrochemical behavior of the materials on symmetrical two-electrode cells using Ce0.9Gd0.1O2-δ as electrolyte. Area specific resistance (ASR) associated to the electrode polarisation process at different temperatures is determined by AC impedance spectroscopy. We found that ordering effects of the crystal structure of the materials have a great impact on ASR values. In general, layered-type ordering of Gd and Ba in the structure decreases ASR values but different types of ordering of anion vacancies also play an important role in the physical properties of these materials.
References:

A. Aguadero, L. Fawcett, S. Taub, R. Woolley, K. T. Wu, N. Xu, J. A. Kilner and S. J. Skinner, J. Mater. Sci. 47 (2012) 3925-3948.

E. Kendrick, P. R. Slater, Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem 109 (2013) 396-420.

A. A. Taskin, A. N. Lavrov and Y. Ando, Appl. Phys. Letters. 86 (2005) 091910.

A. A. Taskin, A. N. Lavrov and Y. Ando, Progress in Solid State Chem. 35 (2007) 481-490.
The Influence of Water in Montmorillonite Clay on the Performance As Electrode Material for Li-Ion Battery/Capacitor
Authors: Chen Chunhui , Shah Gautam , Wang Chunlei 
Published: February 2020

Recently, 2D materials have attracted great attention as electrode materials for lithium ion batteries due to their special electochemical properties. Clays are nature abundant materials which have 2D layered structures. Montmorillonite (MMT) is one of them and composed of units made up of two silica tetrahedral sheets with a central alumina octahedral sheet. The cation and water content in inter layer varies with source. Unlike graphene related materials, electrochemical properties of MMT has rarely been studied. Our recent research shows that MMT could be used as a green electrode material for Li-ion battery/capacitor. Here in this study, we will exam the influence of water in MMT clay on the electrochemical performance.
The performance of various status of MMT, in nature or dehydrated, will be exam. Conductive agent will also be added to improve conductivity of MMT electrode. Both traditional slurry casting and electrostatic spray deposition (ESD) will be used to fabricate the electrode. Fig. 1(a) shows the TEM image of nature MMT clay and (b) cyclic voltammetry (CV) curves of slurry casting MMT electrode. More detailed results will be shown during the meeting.

Figure 1