INFLUENCE OF ALUMINUM ON PHYSICO-CHEMICAL PROPERTIES OF LITHIUM IRON PHOSPHATE

2011 ◽  
Vol 04 (02) ◽  
pp. 123-127 ◽  
Author(s):  
MUNEHIRO KIMURA ◽  
KONRAD ŚWIERCZEK ◽  
JACEK MARZEC ◽  
JANINA MOLENDA
Keyword(s):  
Electrical Conductivity ◽  
Chemical Composition ◽  
Lithium Batteries ◽  
Lithium Iron Phosphate ◽  
Chemical Properties ◽  
Iron Phosphate ◽  
Electrochemical Tests ◽  
Physico Chemical ◽  
Spectroscopy Studies ◽  
Initial Results

In this work we present results of measurements of structural (XRD), microstructural (SEM, EDX, TEM) and transport (electrical conductivity, Seebeck coefficient) properties as well as results of Mössbauer and FTIR spectroscopy studies of phospho-olivine materials with assumed chemical composition Li 1-3x Al x FePO 4 (x = 0, 0.001, 0.005, 0.01, 0.02, 0.05 and 0.1). Based on the performed research, possibility of lithium sublattice doping by Al is discussed. Additionally, initial results of electrochemical tests of lithium batteries with obtained, phospho-olivine based cathode materials are provided.

scholarly journals Morphology and Electrical Conductivity of Carbon Nanocoatings Prepared from Pyrolysed Polymers

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Marcin Molenda ◽  
Michał Świętosławski ◽  
Marek Drozdek ◽  
Barbara Dudek ◽  
Roman Dziembaj
Keyword(s):  
Electrical Conductivity ◽  
Electrode Materials ◽  
Lithium Iron Phosphate ◽  
Solid Phase ◽  
Scale Up ◽  
Iron Phosphate ◽  
Battery Cell ◽  
Pyromellitic Acid ◽  
Specific Morphology ◽  
Precursor Composition

Conductive carbon nanocoatings (conductive carbon layers—CCL) were formed onα-Al2O3model support using three different polymer precursors and deposition methods. This was done in an effort to improve electrical conductivity of the material through creating the appropriate morphology of the carbon layers. The best electrical properties were obtained with use of a precursor that consisted of poly-N-vinylformamide modified with pyromellitic acid (PMA). We demonstrate that these properties originate from a specific morphology of this layer that showed nanopores (3-4 nm) capable of assuring easy pathways for ion transport in real electrode materials. The proposed, water mediated, method of carbon coating of powdered supports combines coating from solution and solid phase and is easy to scale up process. The optimal polymer carbon precursor composition was used to prepare conductive carbon nanocoatings on LiFePO4cathode material. Charge-discharge tests clearly show that C/LiFePO4composites obtained using poly-N-vinylformamide modified with pyromellitic acid exhibit higher rechargeable capacity and longer working time in a battery cell than standard carbon/lithium iron phosphate composites.

scholarly journals Physico-chemical Parameters of Honey From Melipona mondury Smith, 1863 (Hymenoptera: Apidae: Meliponini)

2018 ◽  
Vol 10 (7) ◽  
pp. 196 ◽  
Author(s):  
Rogério Marcos de Oliveira Alves ◽  
Jacqueline Lemos Viana ◽  
Henrique de Abreu Cerqueira Sousa ◽  
Ana Maria Waldschmidt
Keyword(s):  
Electrical Conductivity ◽  
Water Activity ◽  
Reducing Sugars ◽  
Chemical Properties ◽  
Northeastern Brazil ◽  
Chemical Parameters ◽  
Technical Regulation ◽  
Mean Values ◽  
Physico Chemical

The physico-chemical properties of honey produced by the stingless bee Melipona mondury from Atlantic Forest in the state of Bahia, northeastern Brazil were evaluated. The evaluated characteristics included: water content, electrical conductivity, pH, acidity, water activity, ashes, diastase, hydroxymethylfurfural (HMF), reducing sugars and saccharose values. The honey samples showed mean values of 29.18% for moisture; 391.5 μS for electrical conductivity; pH of 4.06; 34.3 meq kg-1 for acidity; 0.73 for water activity; 0.18% for ashes; 4.05 (Goethe unit) for diastase; 1.60% for HMF; 65.42% for reducing sugars; and 2.14% of saccharose. Only the diastase activity was above the limits accepted by the Technical Regulation for Identity and Quality of Honey (Brazilian Ministry of Agriculture and Supplies). Most parameters are according to those reported in honeys from other species of stingless bees in Brazil.

Working Fluids Used for Drilling Deep Boreholes

2014 ◽  
Vol 508 ◽  
pp. 150-155 ◽  
Author(s):  
Marian Šofranko ◽  
Erika Škvareková ◽  
Gabriel Wittenberger
Keyword(s):  
Chemical Composition ◽  
Drilling Fluid ◽  
Chemical Properties ◽  
Proper Function ◽  
Working Fluids ◽  
Physico Chemical ◽  
Geological Conditions ◽  
Deep Boreholes ◽  
Selection Of

Particularly important is the use of drilling fluid in carrying out drilling works to great depths and especially in difficult geological conditions. Proper function of the drilling fluid is governed by the selection of their physico-chemical properties. Drilling works of hydrogeological survey require circulation of borehole with such rinses, which at a minimum pollute water-bearing horizons and their chemical composition meets hygiene requirements.

scholarly journals Physico-chemical properties of Brazilian cocoa butter and industrial blends. Part I Chemical composition, solid fat content and consistency

2012 ◽  
Vol 63 (1) ◽  
pp. 79-88 ◽  
Author(s):  
A. P. B. Ribeiro ◽  
R. Claro da Silva ◽  
L. A. Gioielli ◽  
M. I. De Almeida Gonçalves ◽  
R. Grimaldi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Cocoa Butter ◽  
Chemical Properties ◽  
Solid Fat Content ◽  
Fat Content ◽  
Solid Fat ◽  
Physico Chemical

scholarly journals Physico-chemical Properties of Solutions of Lithium Bis(fluorosulfonyl)imide (LiFSI) in Dimethyl Carbonate, Ethylene Carbonate, and Propylene Carbonate

2021 ◽  
Author(s):  
Johannes Neuhaus ◽  
Erik von Harbou ◽  
Hans Hasse
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Propylene Carbonate ◽  
Dimethyl Carbonate ◽  
Ethylene Carbonate ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Solvent System ◽  
Empirical Correlations ◽  
Physico Chemical

Battery performance strongly depends on the choice of the electrolyte-solvent system. Lithium bis(fluorosulfonyl)imide (LiFSI) is a highly interesting novel electrolyte. Information on physico-chemical properties of solutions of LiFSI, however, is scarce. Therefore, the density, shear viscosity, and electrical conductivity of solutions of LiFSI in three pure solvents that are interesting for battery applications: dimethyl carbonate (DMC), ethylene carbonate (EC), and propylene carbonate (PC), were studied experimentally at temperatures between 273 K and 333 K at 1 bar and concentrations of LiFSI up to 0.45 mol mol−1 in the present work. Empirical correlations of the experimental data are provided. The comparison of the data of this work with the corresponding LiPF6 data underpins the attractiveness of LiFSI as an electrolyte in lithium ion batteries.

“Hydrotriphylites” Li1-xFe1+x(PO4)1-y(OH)4y as Cathode Materials for Li-ion Batteries

2019 ◽  
Author(s):  
Vasily D. Sumanov ◽  
Dmitry A. Aksyonov ◽  
Oleg A. Drozhzhin ◽  
Igor A. Presniakov ◽  
Alexey V. Sobolev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Cathode Materials ◽  
Lithium Iron Phosphate ◽  
Renewable Energy Sources ◽  
Rate Capability ◽  
Iron Phosphate ◽  
Hydroxyl Groups ◽  
Ion Diffusion ◽  
Li Ion

Lithium iron phosphate LiFePO<sub>4</sub> triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are important for broad implementation of the renewable energy sources. Despite the apparent simplicity of its crystal structure and chemical composition, LiFePO<sub>4</sub> is prone to off-stoichiometry and demonstrates rich defect chemistry owing to variations in the cation content and iron oxidation state, and to the redistribution of the cations and vacancies over two crystallographically distinct octahedral sites. The importance of the defects stems from their impact on the electrochemical performance, particularly on limiting the capacity and rate capability through blocking the Li ion diffusion along the channels of the olivine-type LiFePO<sub>4</sub> structure. Up to now the polyanionic (i.e. phosphate) sublattice has been considered idle on this playground. Here, we demonstrate that under hydrothermal conditions up to 16% of the phosphate groups can be replaced with hydroxyl groups yielding the Li<sub>1-x</sub>Fe<sub>1+x</sub>(PO<sub>4</sub>)<sub>1-y</sub>(OH)<sub>4y</sub> solid solutions, which we term “hydrotriphylites”. This substitution has tremendous effect on the chemical composition and crystal structure of the lithium iron phosphate causing abundant population of the Li-ion diffusion channels with the iron cations and off-center Li displacements due to their tighter bonding to oxygens. These perturbations trigger the formation of an acentric structure and increase the activation barriers for the Li-ion diffusion. The “hydrotriphylite”-type substitution also affects the magnetic properties by progressively lowering the Néel temperature. The off-stoichiometry caused by this substitution critically depends on the overall concentration of the precursors and reducing agent in the hydrothermal solutions, placing it among the most important parameters to control the chemical composition and defect concentration of the LiFePO<sub>4</sub>-based cathodes.

scholarly journals Estimating Degradation Costs for Non-Cyclic Usage of Lithium-Ion Batteries

2020 ◽  
Vol 10 (15) ◽  
pp. 5330
Author(s):  
Tomás Cortés-Arcos ◽  
Rodolfo Dufo-López ◽  
José L. Bernal-Agustín
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Batteries ◽  
Lithium Iron Phosphate ◽  
Optimization Problems ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Deterministic Models ◽  
Nickel Cobalt ◽  
Degradation Models ◽  
Battery Degradation

Estimating the degradation costs of lithium-ion batteries is essential to the designs of many systems because batteries are increasingly used in diverse applications. In this study, cyclic and calendar degradation models of lithium batteries were considered in optimization problems with randomized non-cyclic batteries use. Such models offer realistic results. Electrical, thermal, and degradation models were applied for lithium nickel cobalt manganese oxide (NMC) and lithium iron phosphate (LFP) technologies. Three possible strategies were identified to estimate degradation costs based on cell models. All three strategies were evaluated via simulations and validated by comparing the results with those obtained by other authors. One strategy was discarded because it overestimates costs, while the other two strategies give good results, and are suitable for estimating battery degradation costs in optimization problems that require deterministic models.

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