scholarly journals Mesoscale Effects of Composition and Calendering in Lithium-Ion Battery Composite Electrodes

2020 ◽  
Vol 17 (4) ◽  
Author(s):  
Bradley L. Trembacki ◽  
David R. Noble ◽  
Mark E. Ferraro ◽  
Scott A. Roberts
Keyword(s):  
Electrical Conductivity ◽  
Surface Area ◽  
Solid Phase ◽  
Effective Conductivity ◽  
Electronic Conductivity ◽  
Particle Surface ◽  
Lithium Ion ◽  
Effective Property ◽  
Composite Electrodes ◽  
Oxide Electrodes

Abstract Macrohomogeneous battery models are widely used to predict battery performance, necessarily relying on effective electrode properties, such as specific surface area, tortuosity, and electrical conductivity. While these properties are typically estimated using ideal effective medium theories, in practice they exhibit highly non-ideal behaviors arising from their complex mesostructures. In this paper, we computationally reconstruct electrodes from X-ray computed tomography of 16 nickel–manganese–cobalt-oxide electrodes, manufactured using various material recipes and calendering pressures. Due to imaging limitations, a synthetic conductive binder domain (CBD) consisting of binder and conductive carbon is added to the reconstructions using a binder bridge algorithm. Reconstructed particle surface areas are significantly smaller than standard approximations predicted, as the majority of the particle surface area is covered by CBD, affecting electrochemical reaction availability. Finite element effective property simulations are performed on 320 large electrode subdomains to analyze trends and heterogeneity across the electrodes. Significant anisotropy of up to 27% in tortuosity and 47% in effective conductivity is observed. Electrical conductivity increases up to 7.5× with particle lithiation. We compare the results to traditional Bruggeman approximations and offer improved alternatives for use in cell-scale modeling, with Bruggeman exponents ranging from 1.62 to 1.72 rather than the theoretical value of 1.5. We also conclude that the CBD phase alone, rather than the entire solid phase, should be used to estimate effective electronic conductivity. This study provides insight into mesoscale transport phenomena and results in improved effective property approximations founded on realistic, image-based morphologies.

Performance Impacts of Tailored Surface Geometry in Li-Ion Battery Cathodes

2013 ◽  
Author(s):  
George J. Nelson
Keyword(s):  
Surface Area ◽  
Solid Phase ◽  
Particle Surface ◽  
Surface Characteristics ◽  
Analytical Models ◽  
Li Ion Battery ◽  
Fractal Structures ◽  
Surface Geometry ◽  
Trade Offs ◽  
Li Ion

Analytical models developed to investigate charge transfer in Li-ion battery cathodes reveal distinct transport regimes where performance may be limited by either microstructural surface characteristics or solid phase geometry. For several cathode materials, particularly those employing conductive additives, surface characteristics are expected to drive these performance limitations. For such electrodes gains in performance may be achieved by modifying surface geometry to increase surface area. However, added surface area may present a diminishing return if complex structures restrict access to electrochemically active interfaces. A series of parametric studies has been performed to better ascertain the merits of complex, tailored surfaces in Li-ion battery cathodes. The interaction between lithium transport and surface geometry is explored using a finite element model in which complex surfaces are simulated with fractal structures. Analysis of transport in these controlled structures permits assessment of scaling behavior related to surface complexity and provides insight into trade-offs in tailoring particle surface geometry.

Electrical Conductivity of Mixed Conductors (YO1.5)x-(CeO2)y-(ZrO2)1-x-y

2007 ◽  
Vol 336-338 ◽  
pp. 424-427
Author(s):  
Xiang Yong Zhou ◽  
Zeng Fan ◽  
Zi Long Tang ◽  
Zhong Tai Zhang
Keyword(s):  
Electrical Conductivity ◽  
Metal Ion ◽  
Solid Phase ◽  
Electronic Conductivity ◽  
Synthesis Method ◽  
Conductivity Measurement ◽  
Fluorite Structure ◽  
Charge Balance ◽  
Phase Synthesis ◽  
Oxygen Ion

The Y2O3-ZrO2 binary system ceramic is considered to be most developed in application to the ZrO2-based materials. A cubic fluorite structure is generally achieved, as the metal ion of the additive (Y) takes place of the Zr4+ and oxygen ion vacancies are produced in the lattice to maintain the charge balance. This leads to almost totally ionic conductivity. The introduction of changeable valued CeO2 can further improve the total electronic conductivity through the defect equilibrium reaction between tetravalent Ce4+ and trivalent Ce3+ at high temperature and reducing atmosphere. In this study, solid phase synthesis method was employed for the preparation of (YO1.5)x-(CeO2)0.08-(ZrO2)0.9-x and (YO1.5)0.05-(CeO2)y- (ZrO2)0.95-y ceramics, while four probe DC conductivity measurement method was also applied under the temperature between 300 to 800°C. The results prove that the concentration of Y3+ is the main contribution of the electrical conductivity at low temperature.

High-Rate Charge/Discharge Properties of Li Ion Secondary Battery Using V2O5/Carbon Composite Electrodes with Carbon Fiber

2006 ◽  
Vol 301 ◽  
pp. 159-162
Author(s):  
Akira Kuwahara ◽  
Shinya Suzuki ◽  
Masaru Miyayama
Keyword(s):  
Carbon Fiber ◽  
Current Density ◽  
High Current Density ◽  
Fiber Composite ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
High Rate ◽  
Composite Electrodes ◽  
High Electronic Conductivity ◽  
Charge Discharge

The charge/discharge properties of V2O5/carbon composites with controlled microstructures were investigated to achieve a high-rate lithium electrode performance. Composite electrodes were synthesized by mixing a V2O5 sol, carbon and a surfactant, followed by drying. V2O5/AB (acetylene black) and V2O5/VGCF (vapor-grown carbon fiber) composite electrodes showed high-rate charge/discharge properties only when they had very high carbon contents. V2O5/ (AB and VGCF) composite electrodes with controlled microstructures exhibited a discharge capacity of 245 mA·h·g-1 at a high current density of 40 A·g-1, which was approximately 70% of that at a low current density of 100 mA·g-1. The improvement in the high-rate charge/discharge properties was attributed to the short lithium ion diffusion distance, large reaction area and high electronic conductivity of those composite electrodes.

Research on Electrochemical Properties of LiMnPO4 Synthesized by High Temperature Solid-Phase Method

2012 ◽  
Vol 487 ◽  
pp. 714-718 ◽  
Author(s):  
Sheng Kui Zhong ◽  
Ying Mei Zhang ◽  
Wei Li ◽  
Yue Bin Xu
Keyword(s):  
High Temperature ◽  
Solid Phase ◽  
Raw Materials ◽  
Particle Surface ◽  
Lithium Ion ◽  
Xrd Analysis ◽  
Spherical Particles ◽  
Phase Method ◽  
Solid Phase Method ◽  
Olivine Structure

LiMnPO4cathode material for lithium ion batteries was synthesized by high temperature solid-phase method using MnCO3, Li2CO3, NH4H2PO4as raw materials. The structure of samples was identified by XRD analysis and the particle surface morphology was examined by SEM. The results of XRD showed that the LiMnPO4sample sintered at 700°C for 20h had single ordered olivine structure. The SEM pattern showed that spherical particles distributed uniformly. Respectively, it figured out that the initial charge and discharge capacities of the samples at 0.05C rate were 133.9 and 66.4mAh•g-1.

scholarly journals LiOH/Coconut Shell Activated Carbon Ratio Effect on the Electrical Conductivity of Lithium Ion Battery Anode Active Material

Molekul ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 235
Author(s):  
Annisa Syifaurrahma ◽  
Arnelli Arnelli ◽  
Yayuk Astuti
Keyword(s):  
Electrical Conductivity ◽  
Activated Carbon ◽  
Lithium Ion Battery ◽  
Surface Area ◽  
Active Material ◽  
Lithium Ion ◽  
Coconut Shell ◽  
Coconut Shell Activated Carbon ◽  
Anode Active Material ◽  
Battery Anode

A lithium ion battery anode active material comprised of LiOH (Li) and coconut shell activated carbon (AC) has been synthesized with Li/AC ratios of (w/w) 1/1, 2/1, 3/1, and 4/1 through the sol gel method. The present study aims to ascertain the best Li/AC ratio that produces an anode active material with the best electrical conductivity value and determine the characteristics of the anode active material in terms of functional groups, surface area, crystallinity, and capacity. Based on the electrical conductivity test using LCR, the active material Li/AC 2/1 had the highest electrical conductivity with a value of 2.064x10-3 Sm-1. The conductivity achieved was slightly smaller than that of the active material with no addition of LiOH on the activated carbon at an electrical conductivity of 5.434x10-3 Sm-1. The FTIR spectra of the activated carbon and Li/AC 2/1 showed differences with in the Li-O-C group absorption at 1075 cm-1 wavenumber and the wide absorption in the area of 547.5 cm-1 that represents Li-O vibration. Based on the results of SAA, the activated carbon had a larger surface area than Li/AC 2/1 at 17.057 m2g-1 and 5.615 m2g-1, respectively. The crystallinity of both active materials was low shown by the widening of the diffraction peaks. Tests with cyclic voltammetry (CV) proved that there was a reduction-oxidation reaction for the two samples in the first cycle with a large charge and discharge capacities of the activated carbon of 150.989 mAh and 92.040 mAh, while for Li/AC 2/1 they were 91.103 mAh and 47.580 mAh.

Nb3O7F Mesocrystals: Orientation Formation and Application in Lithium Ion Capacitors

CrystEngComm ◽  
2021 ◽  
Author(s):  
Zhijie Chen ◽  
Zhiwei Li ◽  
Wenjie He ◽  
Yufeng An ◽  
Laifa Shen ◽  
...  
Keyword(s):  
Energy Storage ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Electrochemical Energy Storage ◽  
Large Specific Surface Area ◽  
High Crystallinity ◽  
Electrochemical Energy

Mesocrystals have received intense attention in electrochemical energy storage field owing to their favourable electronic conductivity, high crystallinity and large specific surface area. However, a critical limitation to the wide...

LiMBO3 (M=Fe, Mn): Potential Cathode for Lithium Ion Batteries

2002 ◽  
Vol 730 ◽  
Author(s):  
Jan L. Allen ◽  
Kang Xu ◽  
Sam S. Zhang ◽  
T. Richard Jow
Keyword(s):  
High Surface ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
High Surface Area ◽  
Lithium Ion ◽  
Composite Electrodes ◽  
Electrically Conductive ◽  
Manganese Phosphate ◽  
Redox Active ◽  
Active Metal

AbstractRecently discovered borates, LiMBO3 (M=Fe, Mn), share similarities with LiFe(Mn)PO4. They are polyanion structures, contain extractable lithium and suffer from low electronic conductivity. They are attractive to replace expensive, less abundant redox metals in current use in cathodes with environmentally friendly iron or manganese. Phosphate or borate groups adjacent to the redox active metal increase the voltage of the redox couple through an inductive effect. The LiFeBO3 discharge curve shows a pseudo-plateau around 2.6 V for the Fe(II) / Fe(III) couple. This study brings to bear techniques to improve electrode conductivity to produce LiMBO3 composite electrodes thus allowing access to some of the high, theoretical specific capacity. At low current, up to 70 percent of lithium could be extracted from LiFeBO3 that was prepared in the presence of high surface area, highly electrically conductive carbon black. Attempts to improve the cathode properties of LiMnBO3 were less successful.

Cathode materials with mixed phases of orthorhombic MoO3 and Li0.042MoO3 for lithium-ion batteries

2020 ◽  
Vol 98 (2) ◽  
pp. 106-113
Author(s):  
Jiayuan Shi ◽  
Li Liu ◽  
Shusen Kang ◽  
Xiaotao Chen ◽  
Bin Shi
Keyword(s):  
Particle Size ◽  
Lithium Ion Batteries ◽  
Surface Area ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Lithium Content ◽  
Manufacturing Complexity ◽  
Enhanced Conductivity ◽  
Surface Breakage

MoO3 is a promising cathode candidate for lithium-ion batteries and its electronic conductivity is usually improved by MoO3lithiation via reaction of MoO3 with LiCl solutions. However, this process might increase the manufacturing complexity and result in surface breakage of MoO3 cathodes. In this paper, by introducing lithium source into MoO3 synthesis, MoO3 can be lithiated through introduction of the Li0.042MoO3 phase into the MoO3 structure. XRD and ICP results indicate that the phase composition and lithium content can be regulated by changing the amount of lithium source in the reaction solutions. FESEM and specific surface area measurements show that the particle size becomes more uniform and the surface area is increased when the degree of MoO3 lithiation is higher. The lithiated MoO3 sample shows better cycling performance than that of pristine MoO3, which is mainly due to the enhanced conductivity and increased surface area of the lithiated MoO3.

Preparation of Tin Nano-Spheres Film Anode Based on Copper-Nickel Nano-Pillars for Lithium Ion Batteries

2011 ◽  
Vol 399-401 ◽  
pp. 1467-1472 ◽  
Author(s):  
Li Bin Kang ◽  
Shi Chao Zhang ◽  
Ruo Xu Lin
Keyword(s):  
Aqueous Solution ◽  
Lithium Ion Batteries ◽  
Surface Area ◽  
Electrochemical Method ◽  
Copper Foil ◽  
Room Temperature ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Current Collector ◽  
Copper Nickel

Tin nano-spheres film was synthesized by electrodeposition based on the copper-nickel nano-pillars which were prepared by electrochemical method on the copper foil in an aqueous solution containing Cu (II) and Ni (II) at room temperature. The morphology, structure and composition of the as-prepared copper-nickel nano-pillars and tin nano-spheres were characterized by SEM, XRD, and EDS. The tin nano-spheres film anode features the large surface area, good electronic conductivity, and adhesion with the current collector, leading to the enhanced performance in lithium-ion batteries.

Revisiting the passivation of stainless steels and other passive CRAs

2018 ◽  
Vol 106 (1) ◽  
pp. 107 ◽  
Author(s):  
Jean- Louis Crolet
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Base Metal ◽  
Stainless Steels ◽  
Electronic Conductivity ◽  
Transport Processes ◽  
General Knowledge ◽  
Inorganic Polymers ◽  
Faraday Cage

All that was said so far about passivity and passivation was indeed based on electrochemical prejudgments, and all based on unverified postulates. However, due the authors’ fame and for lack of anything better, the great many contradictions were carefully ignored. However, when resuming from raw experimental facts and the present general knowledge, it now appears that passivation always begins by the precipitation of a metallic hydroxide gel. Therefore, all the protectiveness mechanisms already known for porous corrosion layers apply, so that this outstanding protectiveness is indeed governed by the chemistry of transport processes throughout the entrapped water. For Al type passivation, the base metal ions only have deep and complete electronic shells, which precludes any electronic conductivity. Then protectiveness can only arise from gel thickening and densification. For Fe type passivation, an incomplete shell of superficial 3d electrons allows an early metallic or semimetallic conductivity in the gel skeleton, at the onset of the very first perfectly ordered inorganic polymers (- MII-O-MIII-O-)n. Then all depends on the acquisition, maintenance or loss of a sufficient electrical conductivity in this Faraday cage. But for both types of passive layers, all the known features can be explained by the chemistry of transport processes, with neither exception nor contradiction.

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