Kinetic Characterization of Single Particles of LiCoO[sub 2] by AC Impedance and Potential Step Methods

Dokko, Kaoru; Mohamedi, Mohamed; Fujita, Yoshihiro; Itoh, Takashi; Nishizawa, Masatoyo; Umeda, Minoru; Uchida, Isamu

doi:10.1149/1.1359197

Cited by 253 publications

(198 citation statements)

References 35 publications

(48 reference statements)

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“…Researchers have proposed a reversible structural phase transition or order-disorder transition in oxide cathodes during cycling to hysteresis in OCP profiles but it has not been definitely proven. [32][33][34] In operando energy dispersive X-ray diffraction (EDXRD) analysis of NCM523 electrodes during electrochemical charge/discharge is necessary to investigate the cause of this voltage hysteresis.…”

Section: Resultsmentioning

confidence: 99%

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode

Verma

Smith

Santhanagopalan

et al. 2017

J. Electrochem. Soc.

116

127

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Galvanostatic intermittent titration technique (GITT) -a popular method for characterizing kinetic and transport properties of battery electrodes -is predicated on the proper evaluation of electrode active area. LiNi 0.5044 Co 0.1986 Mn 0.2970 O 2 (NCM523) material exhibits a complex morphology in which sub-micron primary particles aggregate to form secondary particle agglomerates. This work proposes a new active area formulation for primary/secondary particle agglomerate materials to better mimic the morphology of NCM532 electrodes. This formulation is then coupled with macro-homogeneous models to simulate GITT and half-cell performance of NCM523 electrodes. Subsequently, the model results are compared against the experimental results to refine the area formulation. A single parameter, the surface roughness factor, is proposed to mimic the change in interfacial area, diffusivity and exchange current density simultaneously and detailed modeling results are presented to provide valuable insights into the efficacy of the formulation. Lithium ion batteries (LIBs) are ubiquitous in energy storage applications. LIBs are versatile and have completely penetrated the consumer electronics market involving low power applications, e.g. mobile phones and laptops.1 In recent years, the use of LIBs in high power applications like electric vehicles is showing great promise. Consequently, vigorous efforts are being directed toward improving its capacity and rate capabilities. LIB energy and power density is directly related to the constituent anode/cathode chemistries. The couples are chosen such that potential difference between the electrodes and Li + ions storage capacity are maximized. Additionally, fast intercalation and diffusion in the solid phase are required for high energy efficiency at high power demands. For anode, graphite has proved to be a valuable material with maximum theoretical capacity estimated at 372 mAh/g graphite combined with open circuit potential close to 0.0 V vs Li for wide range of state of charge. Graphite as an anode material shows robust cycling performance, decent rate capabilities and satisfactory thermal stability.3,4 Current cathodes generally exhibit lower theoretical capacity compared to anodes. Thus, a significant share of research efforts have been concentrated on finding and characterizing novel LIB cathode materials.Several It is apparent that GITT and EIS have emerged as robust electrochemical techniques for battery material characterization. However, extraction of accurate kinetic and transport quantities from GITT and EIS necessitates the precise computation of interfacial area, which gets even more complicated for NCM523 particle agglomerates exhibiting bimodal particle size distribution. Thus, it becomes imperative to design first an accurate mathematical descriptor of active area for NCM523 electrodes. This estimate is then coupled with macro homogeneous performance models to simulate GITT and half-cell performance of NCM523 electrodes. Refinement of the area estimates is execut...

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Section: Resultsmentioning

confidence: 99%

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode

Verma

Smith

Santhanagopalan

et al. 2017

J. Electrochem. Soc.

116

127

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“…Dokko et al has developed a new measurement technology for evaluation of electrochemical properties of active materials by using one (single) particle. 10 In this measurement, there is no effect of porous nature of composite electrode. Another useful method is an electrochemical measurement with a thin film of active material.…”

Section: Introductionmentioning

confidence: 87%

Electrochemical Evaluation of Active Materials for Lithium Ion Batteries by One (Single) Particle Measurement

et al. 2016

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A one (single) particle measurement was employed to estimate electrochemical parameters of active materials for lithium ion batteries in order to design porous electrodes and cells. A micro electrode was used as a current collector for LiCoO 2 and graphite particles. In the cases of materials with large expansion and shrinkage during discharge and charge process, a tweezers-type current collector was developed and applied to the measurement. Si particle as an anode material for post lithium ion batteries was measured by using a tweezers-type current collector to stabilize a contact between active material and current collector. Successfully, the tweezers-type current collector provided a stable contact to the active material particle. The electrochemical parameters for various active materials were obtained from the one (single) particle measurement. Based on these parameters, the porous electrode and lithium ion cell can be designed.

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“…32 Dokko et al reported that contact resistance does not affect the electrochemical characteristics of LiCoO 2 particles. 33 To examine the electrochemical uniformity of the particles, the dependence of the discharge rate characteristics of the contact point between the Pt microprobe and a needle-like LiCoO 2 crystal was determined. The Pt microprobe was placed in contact with the center and both side edges of the LiCoO 2 particle, as shown in Fig.…”

Section: ¹1mentioning

confidence: 99%

Intrinsic Electrochemical Characteristics in the Individual Needle-like LiCoO<sub>2</sub> Crystals Synthesized by Flux Growth

et al. 2017

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The intrinsic electrochemical characteristics of needle-like LiCoO 2 crystals with a hexagonal cylindrical shape were studied by the single particle measurement technique. The needle-like LiCoO 2 crystals were synthesized by the flux growth method. Single-particle Raman spectroscopy and galvanostatic charge-discharge tests at different electrical contact points in one needle-like LiCoO 2 crystal revealed that the crystal has homogeneous intercalation/ deintercalation characteristics throughout the long axis. This suggests that the electron conductivity is high on a 100 µm scale along that axis and that lithium ions are efficiently transferred from the electrolyte to the layer structure of the crystal. The charge rate characteristics of the needle-like LiCoO 2 crystals were also evaluated and compared to those of powdered LiCoO 2 . The polarization curve analysis indicates that the needle-like LiCoO 2 particles had almost same exchange current density, i 0 , as powdered LiCoO 2 , which has a much smaller volume. These excellent electrochemical characteristics are considered to be due to the orientation of the {104} crystal face on the crystal sides, which is the preferential face for lithium ion transfer, and the larger effective surface area of the particles.

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Kinetic Characterization of Single Particles of LiCoO[sub 2] by AC Impedance and Potential Step Methods

Cited by 253 publications

References 35 publications

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode

Electrochemical Evaluation of Active Materials for Lithium Ion Batteries by One (Single) Particle Measurement

Intrinsic Electrochemical Characteristics in the Individual Needle-like LiCoO<sub>2</sub> Crystals Synthesized by Flux Growth

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Kinetic Characterization of Single Particles of LiCoO[sub 2] by AC Impedance and Potential Step Methods

Cited by 253 publications

References 35 publications

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi0.5Co0.2Mn0.3O2Cathode

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi0.5Co0.2Mn0.3O2Cathode

Electrochemical Evaluation of Active Materials for Lithium Ion Batteries by One (Single) Particle Measurement

Intrinsic Electrochemical Characteristics in the Individual Needle-like LiCoO<sub>2</sub> Crystals Synthesized by Flux Growth

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Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi_0.5Co_0.2Mn_0.3O₂Cathode