On the electrochemical impedance response of composite insertion electrodes – Toward a better understanding of porous electrodes

Gruet, David; Delobel, Bruno; Sicsic, David; Lucas, Ivan T.; Vivier, Vincent

doi:10.1016/j.electacta.2018.10.115

Cited by 37 publications

(35 citation statements)

References 29 publications

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“…As illustrated in Fig. 4e the diameter of the semi-circle region becomes smaller with the increase in deposition charge, where it is governed by the electrode thickness, porosity and integrity of the Au-PEDOT-CNF composite interface [67,68]. Among all the deposition conditions, 4 nC/µm 2 and 6 nC/µm 2 clearly showed depressed semi-circle regions, thus reflecting the improved area and highly conductive surface of the electrodes with lower impedance, possessing the capability of seamless bidirectional transfer of charges/electrons.…”

Section: Cscc and Eis Measurementsmentioning

confidence: 93%

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Vajrala

Saunier

Nowak

et al. 2021

Preprint

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In this study, we report a flexible implantable 4-channel microelectrode probe coated with highly porous and robust nanocomposite of poly(3,4-ethylenedioxythiophene) (PEDOT) and carbon nanofiber (CNF) as a solid doping template for high-performance in vivo neuronal recording and stimulation. A simple yet well-controlled deposition strategy was developed via in situ electrochemical polymerization technique to create a porous network of PEDOT and CNFs on a flexible 4-channel gold microelectrode probe. Different morphological and electrochemical characterizations showed that they exhibit remarkable and superior electrochemical properties, yielding microelectrodes combining high surface area, low impedance (16.8 Mohm.micrometer2 at 1 kHz) and elevated charge injection capabilities (7.6 mC/cm2) that exceed those of pure and composite PEDOT layers. In addition, the PEDOT-CNF composite electrode exhibited extended biphasic charge cycle endurance, resulting in a negligible physical delamination or degradation for long periods of electrical stimulation. In vitro testing on mouse brain slices showed that they can record spontaneous oscillatory field potentials as well as single-unit action potentials and allow to safely deliver electrical stimulation for evoking field potentials. The combined superior electrical properties, durability and 3D microstructure topology of the PEDOT-CNF composite electrodes demonstrate outstanding potential for developing future neural surface interfacing applications

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Section: Cscc and Eis Measurementsmentioning

confidence: 93%

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Vajrala

Saunier

Nowak

et al. 2021

Preprint

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“…To follow up further the investigation of the influence of the electrode surface area on the electrode performance, Nyquist plots were made to monitor the evolution of charge transfer resistance (semi-circle region) as a function of deposition charge (Gruet et al, 2019;Huang et al, 2020). Among all the deposition conditions, 4 nC/µm 2 and 6 nC/µm 2 clearly showed depressed semi-circle regions, thus reflecting the improved area and highly conductive surface of the electrodes with lower impedance, possessing the capability of seamless bidirectional transfer of charges/electrons.…”

Section: Cscc and Eis Measurementsmentioning

confidence: 99%

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Vajrala

Saunier

Nowak

et al. 2021

Front. Bioeng. Biotechnol.

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In this study, we report a flexible implantable 4-channel microelectrode probe coated with highly porous and robust nanocomposite of poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanofiber (CNF) as a solid doping template for high-performance in vivo neuronal recording and stimulation. A simple yet well-controlled deposition strategy was developed via in situ electrochemical polymerization technique to create a porous network of PEDOT and CNFs on a flexible 4-channel gold microelectrode probe. Different morphological and electrochemical characterizations showed that they exhibit remarkable and superior electrochemical properties, yielding microelectrodes combining high surface area, low impedance (16.8 ± 2 MΩ µm2 at 1 kHz) and elevated charge injection capabilities (7.6 ± 1.3 mC/cm2) that exceed those of pure and composite PEDOT layers. In addition, the PEDOT-CNF composite electrode exhibited extended biphasic charge cycle endurance and excellent performance under accelerated lifetime testing, resulting in a negligible physical delamination and/or degradation for long periods of electrical stimulation. In vitro testing on mouse brain slices showed that they can record spontaneous oscillatory field potentials as well as single-unit action potentials and allow to safely deliver electrical stimulation for evoking field potentials. The combined superior electrical properties, durability and 3D microstructure topology of the PEDOT-CNF composite electrodes demonstrate outstanding potential for developing future neural surface interfacing applications.

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“…2πT BDW (33) where the pre-factor 3.8875 represents the converged solution of sk in the iterative process of Eq. and expressed in Table II and When p = 0.78 in the BDW, the frequency − , calculated through Eq.…”

Section: Estimation Of − In the Bdw Impedancementioning

confidence: 99%

“…20 and the parameters R W = 0.001, T BDW = 1.4 p = 0.78 estimated in a previous study [32] and with a range of frequencies f = 10 kHz − 0.001 Hz. Gruet et al [33] developed an impedance model for porous electrodes in Li-ion batteries and considered diffusion coefficients reported in the study of Smith et al [34]. The diffusion coefficients were estimated using a higher order CFD model [35].…”

Section: Estimation Of − In the Bdw Impedance Response Of A Li-ion Bamentioning

confidence: 99%

Frequency Transition from Diffusion to Capacitive Response in the Blocked-Diffusion Warburg Impedance for EIS Analysis in Modern Batteries

Cruz-Manzo¹,

Greenwood²

2020

J. Electrochem. Soc.

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The use of the Blocked-diffusion Warburg (BDW) impedance within electrochemical impedance spectroscopy (EIS) measurements can unveil diffusion properties of the electroactive material of modern batteries at different states-of-charge. The impedance response of the BDW comprises a diffusion response of charge carriers through a shortdiffusion distance (e.g. the solid-phase in electroactive material of battery electrodes) and a capacitive response due to accumulation of charge carriers in a blocked-interface (e.g. impermeable current collector of a thin film electrode). This study has developed a mathematical expression based on the Newton-Raphson iteration method to calculate the frequency and time constant during the transition from diffusion to capacitive response in the BDW impedance. The mathematical procedure to calculate the frequency during the diffusioncapacitive transition response in the BDW has been written in a script in Matlab® software and is applied to BDW impedance responses reported in previous studies and extracted from EIS measurements in Li-ion and NiMH batteries. This study demonstrates that the time constant during the transition from diffusion to capacitive response in the BDW differs from the characteristic time constant commonly represented in the BDW mathematical expression. The characteristic time constant represented in the BDW mathematical expression is related to the rate of accumulation of charge carriers in the blocked-interface of the electrode. On the other hand, the time constant during the transition from diffusion to capacitance responses in the BDW impedance can be related to diffusion properties in solid-phase particles with heterogeneous size distribution in the electroactive material of modern battery electrodes.

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On the electrochemical impedance response of composite insertion electrodes – Toward a better understanding of porous electrodes

Cited by 37 publications

References 29 publications

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing

Frequency Transition from Diffusion to Capacitive Response in the Blocked-Diffusion Warburg Impedance for EIS Analysis in Modern Batteries

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