New coordination complexes as electrodes for ion battery system

International audienc

New coordination complexes as electrodes for ion battery system

International audienc

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienceLi-ion batteries despite being the most commercialised electrochemical energy storage system are still suffering some drawbacks during their cycling. Indeed, several processes are taking place during cycling, i) the electrodes are “breathing” during oxidation and reduction, ii) the electrolyte is reduced and oxidised generating several surface reactions among them the well-known solid electrolyte interphase (SEI). As an example, at the negative electrode, graphite is suffering a volume expansion of up to 10% that is generally reversible but upon long-term cycling can be a caused of fading (ref.1). This induced mechanical stress and its consequence on the electrochemical performance need to be investigated

Analysis of Limiting Processes of Power Performance Within Li-ion Batteries

International audienceLi-ion batteries have become a necessity in human daily life as the most versatile, efficient and performing energy storage & conversion system to power our nomad electronic, cars and buffer the renewable intermittent energy sources.1 However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, and cycle life. Besides the active materials, among the strategies to increase battery autonomy, one consists of optimizing the design parameters of the electrode such as the formulation, loading, microstructure, and porosity. The idea is simply to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…). However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is ultimatelyto optimize the battery design to find the best compromise between energy and power density in Li-based batteries.2 In this work, we study Li-battery capacity as a function of the current density with respect to electrode porosity, formulation, loading, microstructure as well as temperature. For this purpose, (LiFePO4)LFP and (LiNi0.8Mn0.1Co0.1O2) NMC-811-based electrodes were formulated at different loadings (from 0.4to 3.4 mAh.cm-2), compositions (Active material%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 50 %). The microstructure of electrodes is investigated using SEM, Granulometryand BET to determine their microstructure and specific area. The electrode tortuosity is analysed through impedance spectroscopy in a symmetric positive/positive electrode.3 Subsequently, the power performanceis fully captured and analyzed using a time-saving methodology.4 The limiting current density, Jlim, isobtained through capacity vs discharge current curves, which allows us to determine an effective diffusioncoefficient of the limiting transport process (Deff) via Sand equation. We also analyse the diffusion coefficient and charge transfer resistance (Rct) as a function of the state of charge (SOC) by coupling GITT and EIS. Afterwards, the correlation between design parameters and the effective electrochemical parameters such as Deff and Jlim, Rct is discusse

Study of limiting factors of power performance within Li-ion batteries

International audienceLi-ion battery is a mature technology widely applied as a power source for consumer electronic devices, and nowadays, their use is expanded towards electric vehicles and stationary applications. However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, cycle life, and costs. Among the strategies to increase battery autonomy, one focuses on electrode loading to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…). However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is to optimize the battery design to find the best compromise between energy and power density in Li metal-based batteries. In this work, we studied Li-battery capacity as a function of the current density with respect to electrode loading, formulation, porosity, microstructure, temperature, and ageing. For this purpose, (LiFePO4) LFP and (LiNi0.8Mn0.1Co0.1O2) NMC-811 based electrodes were formulated at different loadings (from 0.4 to 3.4 mAh.cm-2), compositions (Active material%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 50 %). The microstructure of electrodes is investigated using SEM and BET to determine their specific area. Subsequently, the power performance is fully captured and analyzed using a time-saving methodology. The limiting current density, Jlim, is obtained through capacity vs discharge current curves, which allows us to determine an effective diffusion coefficient of the limiting transport process (Deff) via the Sand equation. Finally, Deff is compared to the diffusion coefficient obtained using the conventional Galvanostatic Intermittent Titration Technique (GITT) to assess the nature of the limiting phenomena such as Li+ diffusion within the solid phase and/or Li+ diffusion in liquid phase through electrode porosity. The coupling of the various processes, as well as the correlation between design parameters and Jlim, are discussed

Analysis of Limiting Processes of Power Performance Within Li-ion Batteries

International audienceLi-ion batteries have become a necessity in human daily life as the most versatile, efficient and performing energy storage & conversion system to power our nomad electronic, cars and buffer the renewable intermittent energy sources.1 However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, and cycle life. Besides the active materials, among the strategies to increase battery autonomy, one consists of optimizing the design parameters of the electrode such as the formulation, loading, microstructure, and porosity. The idea is simply to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…). However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is ultimatelyto optimize the battery design to find the best compromise between energy and power density in Li-based batteries.2 In this work, we study Li-battery capacity as a function of the current density with respect to electrode porosity, formulation, loading, microstructure as well as temperature. For this purpose, (LiFePO4)LFP and (LiNi0.8Mn0.1Co0.1O2) NMC-811-based electrodes were formulated at different loadings (from 0.4to 3.4 mAh.cm-2), compositions (Active material%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 50 %). The microstructure of electrodes is investigated using SEM, Granulometryand BET to determine their microstructure and specific area. The electrode tortuosity is analysed through impedance spectroscopy in a symmetric positive/positive electrode.3 Subsequently, the power performanceis fully captured and analyzed using a time-saving methodology.4 The limiting current density, Jlim, isobtained through capacity vs discharge current curves, which allows us to determine an effective diffusioncoefficient of the limiting transport process (Deff) via Sand equation. We also analyse the diffusion coefficient and charge transfer resistance (Rct) as a function of the state of charge (SOC) by coupling GITT and EIS. Afterwards, the correlation between design parameters and the effective electrochemical parameters such as Deff and Jlim, Rct is discusse

Analysis of limiting Processes within Li-ion Batteries

International audienceLi-ion battery is a mature technology widely applied as a power source for consumer electronic devices, and nowadays, their use is expanded towards electric vehicles and stationary applications. However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, cycle life, and costs. Among the different strategies to increase battery autonomy, one is focusing on electrode loading to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…) . However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is to optimize the battery design to find the best compromise between energy and power density in Li metal-based batteries. In this work, we studied Li-battery capacity as a function of the current density with respect to electrode loading, formulation, porosity, and aging. For this purpose, (LiFePO4) LFP based electrodes were formulated at different loadings (from 0.4 to 3.2 mAh.cm-2), compositions (LFP%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 60 %). The microstructure of electrodes is investigated using SEM and BET to determine their specific area. Subsequently, the power performance is fully captured and analyzed using a time-saving methodology. The limiting C-rate (resp. current density, Jlim) is obtained through capacity vs. discharge current curves, which allows us to determine an effective diffusion coefficient of the limiting transport process (Deff) via the Sand equation.Finally, Deff is compared to the diffusion coefficient obtained using the conventional alvanostatic Intermittent Titration Technique (GITT) to assess the nature of the limiting phenomena such as Li+ diffusion within the solid phase and/or Li+diffusion in liquid phase through electrode porosity. The coupling of the various processes according to the studied parameters is discusse

Investigating Li-ion batteries negative electrode swelling processes using electrochemical dilatometer

International audienceLi-ion batteries despite being the most commercialised electrochemical energy storage system are still suffering some drawbacks during their cycling. Indeed, several processes are taking place during cycling, i) the electrodes are “breathing” during oxidation and reduction, ii) the electrolyte is reduced and oxidised generating several surface reactions among them the well-known solid electrolyte interphase (SEI)

Analysis of limiting Processes within Li-ion Batteries

International audienceLi-ion battery is a mature technology widely applied as a power source for consumer electronic devices, and nowadays, their use is expanded towards electric vehicles and stationary applications. However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, cycle life, and costs. Among the different strategies to increase battery autonomy, one is focusing on electrode loading to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…) . However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is to optimize the battery design to find the best compromise between energy and power density in Li metal-based batteries. In this work, we studied Li-battery capacity as a function of the current density with respect to electrode loading, formulation, porosity, and aging. For this purpose, (LiFePO4) LFP based electrodes were formulated at different loadings (from 0.4 to 3.2 mAh.cm-2), compositions (LFP%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 60 %). The microstructure of electrodes is investigated using SEM and BET to determine their specific area. Subsequently, the power performance is fully captured and analyzed using a time-saving methodology. The limiting C-rate (resp. current density, Jlim) is obtained through capacity vs. discharge current curves, which allows us to determine an effective diffusion coefficient of the limiting transport process (Deff) via the Sand equation.Finally, Deff is compared to the diffusion coefficient obtained using the conventional alvanostatic Intermittent Titration Technique (GITT) to assess the nature of the limiting phenomena such as Li+ diffusion within the solid phase and/or Li+diffusion in liquid phase through electrode porosity. The coupling of the various processes according to the studied parameters is discusse