Solid‐State Electrochemical Kinetics of Li‐Ion Intercalation into Li1 − x CoO2: Simultaneous Application of Electroanalytical Techniques SSCV, PITT, and EIS

Abstract

The electroanalytical behavior of thin Li1−xCoO2 electrodes is elucidated by the simultaneous application of three electroanalytical techniques: slow‐scan‐rate cyclic voltammetry (SSCV), potentiostatic intermittent titration technique, and electrochemical impedance spectroscopy. The data were treated within the framework of a simple model expressed by a Frumkin‐type sorption isotherm. The experimental SSCV curves were well described by an equation combining such an isotherm with the Butler‐Volmer equation for slow interfacial Li‐ion transfer. The apparent attraction constant was −4.2, which is characteristic of a quasi‐equilibrium, first‐order phase transition. Impedance spectra reflected a process with the following steps: Li+ ion migration in solution, Li+ ion migration through surface films, strongly potential‐dependent charge‐transfer resistance, solid‐state Li+ diffusion, and accumulation of the intercalants into the host materials. An excellent fit was found between these spectra and an equivalent circuit, including a Voigt‐type analog ( Li+ migration through multilayer surface films and charge transfer) in series with a finite‐length Warburg‐type element ( Li+ solid‐state diffusion), and a capacitor (Li accumulation). In this paper, we compare the solid‐state diffusion time constants and the differential intercalation capacities obtained by the three electroanalytical techniques. © 1999 The Electrochemical Society. All rights reserved.

Multiscale modelling and analysis of lithium-ion battery charge and discharge

“…Typically, it is hypothesised that the reaction rate depends upon the Li concentration on the electrode surface, Li + concentration in the adjacent electrolyte and the potential drop between the electrode and electrolyte (see, e.g. [8,13,14]). The reaction, and thus the corresponding release of charge, may thus be limited by diffusion of Li + in the electrolyte, diffusion of Li in the electrode material or by the electrical resistivity of the electrolyte or electrodes, and it is important to investigate the relative importance of these processes.…”

Impedance Analysis with Transmission Line Model for Reaction Distribution in a Pouch Type Lithium-Ion Battery by Using Micro Reference Electrode

“…The two semicircles for the cathode confirmed at several kHz and several Hz are attributed to lithium migration in the surface film and to charge transfer, respectively. 45 It is noteworthy that a 45 degree slope with respect to the real axis in the limit of a semi-infinitely deep pore was clearly observed in the Nyquist plots enlarged at the region between the high and middle frequency for the cathode (Fig. 6e); whereas, a corresponding slope could not be observed for the anode (Fig.…”

“…The increase in R ct value of the cathode is in accordance with results from previous studies. 45,49,50 This increase is partly due to the variation of electronic conductivity in the active material, Li x CoO 2.…”

Capacity Fade Study of LiCo0.4Al0.1Mn1.5O4 Cathode Material for Li-Ion Batteries Cycled at Low Discharge Rates

“…These values indicate the electrode-electrolyte interface layer after charge-discharge cycle [36]. The pristine sample show high frequency semi circle, which represents the migration of Li + ions at the electrode-electrolyte interface [37,38]. A straight line in low frequency region corresponds to the charge-transfer process.…”