On the correlation between the electroanalytical behavior and crystallographic features of Li-intercalation electrodes

• Published in: Journal of power sources Vol. 97; pp. 525 - 528
• Main Authors: Levi, M.D., Levi, E., Aurbach, D., Schmidt, M., Oesten, R., Heider, U.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01.07.2001; Elsevier Sequoia
• Subjects: Applied sciences; Chemical diffusion coefficient of Li-ions; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Impedance spectroscopy; Li xNiO 2 and Li xCo 0.2Ni 0.8O 2 electrodes; Lithium rechargeable batteries; Chemical diffusion coefficient of Li-ions; Impedance spectroscopy; Lithium rechargeable batteries; Li x NiO 2 and Li x Co 0.2Ni 0.8O 2 electrodes; Cobalt oxide; Ternary compound; Performance evaluation; Alkali metal Compounds; Transition metal Compounds; Secondary cell; Electrode material; Electric batteries; Intercalation compound; Transport process; Metal metal oxide batteries; Quaternary compound; Organic electrolyte storage battery; Lithium oxide; Chemical diffusion; Nickel oxide
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/S0378-7753(01)00667-X

The electroanalytical behavior of Li x NiO 2 and Li x Co 0.2Ni 0.8O 2 was studied by simultaneous application of slow-scan rate cyclic voltammetry (SSCV), potentiostatic and galvanostatic intermittent titration (PITT and GITT), and electrochemical impedance spectroscopy (EIS). Application of a finite-space diffusion model for treating the results obtained by these techniques allowed us to calculate the diffusion coefficient of Li ions ( D) and the differential (incremental) capacity ( C int) as functions of the electrode’s potential. Our final purpose was to compare D versus E and C int versus E plots for both the electrodes, in order to correlate the observed difference in their electroanalytical behavior with the clear distinction in the related Li-insertion mechanisms deduced from XRD studies. While Li insertion into Li x Co 0.2Ni 0.8O 2 exhibits a single-phase reaction upon charge in the 3.0–4.08 V (versus Li/Li +) range, Li intercalation into Li x NiO 2 undergoes two-phase transitions in the same potential range. The shape of both plots, D versus E and C int versus E for these electrodes, is discussed in the framework of a finite-space diffusion model and Li-insertion processes that can be described by Frumkin-type intercalation isotherms with short-range attraction interactions among intercalation sites.