Lithium ion battery performance at high charge/discharge rates is largely determined by the ionic resistivity of an electrode and separator which are filled with electrolyte. Key to understand model ohmic losses in porous components porosity as well tortuosity. In first part, we use impedance spectroscopy measurements a new experimental setup obtain tortuosities MacMullin numbers some commonly used separators, demonstrating errors <8%. second present electrodes symmetric cells using blocking...

Lithium-ion battery performance at low temperatures or fast charge/discharge rates is determined by the intrinsic electrolyte transport and thermodynamic properties of commonly used binary electrolytes. For development future solutions, a quantification ionic conductivity, diffusion coefficient, transference number, factor over large concentration temperature range mandatory. In this study, we apply previously discussed established methods for determination conductivities coefficients to two...

Impedance measurements of lithium-ion batteries are a powerful tool to investigate the electrolyte/electrode interface. To separate contributions anode and cathode full-cell impedance, reference electrode is required. However, if placed inappropriately, impedance response can easily be biased lead erroneous conclusions. In this study, we present novel micro-reference for Swagelok-type T-cells which suitable long-term potential measurements. The consists thin insulated gold wire, centrally...

A key for the interpretation of porous lithium ion battery electrode impedance spectra is a meaningful and physically motivated equivalent-circuit model. In this work we present novel approach, utilizing general transmission line model to exemplarily analyze high-voltage LiNi0.5Mn1.5O4 (LNMO) cathode. It based on LNMO/graphite full-cell setup equipped with gold wire micro-reference (GWRE) obtain in both, non-blocking conditions at potential 4.4 V cell voltage blocking configuration achieved...

Tortuosity values of porous battery electrodes determined using electrochemical impedance spectroscopy in symmetric cells with a non-intercalating electrolyte are typically higher than those based on numerical analysis 3D tomographic reconstructions. The approach assumes that the electronic resistance coating is negligible and tortuosity electrode can be calculated from ionic by fitting transmission line equivalent circuit model to experimental data. In this work, we validate assumptions...

The electrochemical performance of porous graphite anodes in lithium ion battery applications is limited by the concentration gradients liquid electrolyte, especially at high current densities and for thick coatings during charging. Beside electrolyte transport parameters, porosity tortuosity coating are key parameters that determine electrode's suitability power applications. Here, we investigate using two water as well three n-methyl-2-pyrrolidone based binder systems analysis symmetric...

Drying battery electrodes at high rates leads to binder migration and has shown affect the mechanical as well electrochemical properties of Li-ion electrodes. Up now, little evidence been why performance suffers. Here, we investigate influence an inhomogeneous distribution on total ionic resistance within electrode. First, model impact that vertical inhomogeneities have impedance spectrum RC (resistor, capacitor) transmission line model. We show how different profiles lead characteristic...

Various numerical methods for the simulation of ion-transport in concentrated binary electrolyte solutions can be found literature, whereas corresponding transport parameters are rarely discussed. In this contribution, a polarization cell consisting two electrodes separated by porous separator is proposed to determine concentration dependent diffusion coefficient non-aqueous solutions. Therefore, different electrochemical extended so that they applied medium. Additionally, compared with each...

Abstract The need to improve electrodes and Li‐ion conducting materials for rechargeable all‐solid‐state batteries has drawn enhanced attention the investigation of lithium‐rich compounds. study ternary system Li‐Si‐P revealed a series new compounds, two which, Li 8 SiP 4 2 , are presented. Both phases represent members family ion conductors that display conductivity in range from 1.15(7)×10 −6 Scm −1 at 0 °C 1.2(2)×10 −4 75 (Li ) 6.1(7)×10 −8 6(1)×10 ), as determined by impedance...

LiNi0.5Mn1.5O4 (LNMO) cathodes cycled versus a graphite anode at elevated temperatures usually show severe capacity fading upon extended charge/discharge cycling. In the literature, impedance increase cathode is often related to formation of so-called cathode/electrolyte interphase (CEI) and presented as one possible failure mechanisms. this study, we that main reason for increasing contact resistance (RCont.) between aluminum current collector electrode rather than surface film (RCEI)....

To bridge the gap between current lithium-ion battery technology and alternative cell chemistries such as, e.g., sodium-ion batteries, majority of research in this field focuses on improvement cell’s energy density by development new active materials for reversible storage sodium ions. On other hand, power density, which is determined ionic transport thermodynamic parameters electrolyte, namely conductivity, factor, transference number, diffusion coefficient, attracting little attention. In...

Lithium-Ion batteries consisting of LNMO (LiNi0.5Mn1.5O4) cathodes and graphite anodes show severe capacity fading at elevated temperatures due to a damage the solid electrolyte interface (SEI) on anode. Hence, detailed investigation anode with electrochemical impedance spectroscopy (EIS) can provide valuable insight into phenomenon degradation. In this study, we use modified version our novel procedure (Part I study), where is measured non-blocking conditions (10% SOC) blocking (0% in...

We propose a novel method to determine the thermodynamic factor of binary salts dissolved in aprotic solvents as function salt concentration. The is based on cyclic voltammetry experiments conducted three-electrode cell with ferrocene/ferrocenium redox couple being used an internal standard. main advantage this experimental setup direct electrochemical determination from single type experiment without necessity additional assumptions other transport parameters. theoretical derivation...

In the literature, various numerical methods for simulation of ion-transport in concentrated binary electrolytes lithium ion batteries can be found, whereas corresponding transport parameters are rarely discussed. this contribution, a novel method determination transference number non-aqueous is proposed. The based on data from concentration cell and value thermodynamic factor obtained independent measurements quantifying redox potential ferrocene. dependent numbers by new compared to values...

In this work, we target to isolate the SEI resistance of graphite electrodes in lithium-ion cells by impedance spectroscopy measured blocking conditions (here = 0% SOC), where charge transfer RCT is significantly enlarged (∼104 Ω cm2geom) and thus corresponding semicircle shifted very low frequencies. Therefore, measure spectra graphite/LFP full with a gold-wire reference electrode (GWRE) (graphite potential 2 V vs Li+/Li, SOC) before after formation. As electrolytes, use LP57 (EC:EMC 3:7 +...

The tortuosity of a porous electrode is one the critical parameters that governs effective transport properties such as conductivity and diffusivity ions in electrolyte phase. While there exist several methods to determine through-plane for lithium-ion battery electrodes, in-plane are scarcely explored. In this paper, we present method restricts ion only direction, which facilitates determination direction. here proposed cell design analyzed using blocking condition transmission line model...

The ionic transport properties of battery materials such as separators can be measured by AC impedance. We show data from two measurement setups and demonstrate how a reliable the high frequency resistance thus tortuosity typical achieved.

For numerical simulations of battery systems, the ion-transport model for concentrated electrolyte solutions introduced by Newman and Thomas-Alyea 1 is frequently used depends on three ion transport parameters: conductivity, transference number binary diffusion coefficient. In addition, thermodynamic factor which derived from mean molar activity coefficient required correct description behavior a solution. A vast spectrum physico-chemical parameters can be found in literature (e.g., Valoen...

Lithium-Ion Batteries containing a high-voltage positive electrode as LiNi 0.5 Mn 1.5 O 4 (LNMO) have high operating voltage and are therefore considered for energy batteries [1]. However, it’s potential (4.75 V vs. Li/Li + ) causes some severe side reactions, especially at elevated temperatures, such electrolyte oxidation transition metal dissolution [2]. A further failure mechanism of graphite/LNMO cells is the increase cell impedance during cycling In literature, spectrum (in Nyquist...

The lifetime of lithium-ion batteries strongly depends on the properties interface between each electrode and electrolyte. Electrochemical impedance spectroscopy is a simple non-destructive method to investigate electrode/electrolyte interfaces effect electrolyte additives. As measurements full-cells always reflect sum both electrodes, it difficult deconvolute contributions cathode anode interface. Therefore, numerous reference designs for have been suggested. 1–6 However, if not placed...

For understanding of existing battery systems such as lithium-ion batteries and for the development future systems, advanced numerical simulation tools are important. One beneficial aspect computational methods is that they can provide insight into physical chemical aspects, which sometimes cannot be probed by experimental methods. Accuracy reliability key issues simulations depend on appropriate models, boundary conditions, accurately determined physico-chemical parameters 1 . ion-transport...

A key to understanding the limitations of lithium ion batteries and for modelling battery performance is knowledge ohmic losses in porous components. In electrolyte filled pores a separator, arise from ionic resistivity. electrode they originate network electronic resistances. We apply impedance spectroscopy measure high frequency resistance separators other literature, many values effective can be found [1,2,3,4], but their usefulness sometimes diminished by unclear definitions tortuosity...