Investigation of Lithium Ion Diffusion of Graphite Anode by the Galvanostatic Intermittent Titration Technique

• Published in: Materials Vol. 14; no. 16; p. 4683
• Main Authors: Park, Jong Hyun, Yoon, Hana, Cho, Younghyun, Yoo, Chung-Yul
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19-08-2021; MDPI
• Subjects: Anodes; Diffusion coefficient; Diffusion rate; Efficiency; Electrochemical impedance spectroscopy; Electrodes; Energy storage; Equilibrium; Experiments; galvanostatic intermittent titration technique; Graphite; Intercalation; Ion concentration; Ion diffusion; Ion storage; Lithium; Lithium-ion batteries; lithium-ion battery; Open circuit voltage; Particle size; quasi-equilibrium open circuit potential; Rechargeable batteries; Storage batteries; Titration
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14164683

Graphite is used as a state-of-the-art anode in commercial lithium-ion batteries (LIBs) due to its highly reversible lithium-ion storage capability and low electrode potential. However, graphite anodes exhibit sluggish diffusion kinetics for lithium-ion intercalation/deintercalation, thus limiting the rate capability of commercial LIBs. In order to determine the lithium-ion diffusion coefficient of commercial graphite anodes, we employed a galvanostatic intermittent titration technique (GITT) to quantify the quasi-equilibrium open circuit potential and diffusion coefficient as a function of lithium-ion concentration and potential for a commercial graphite electrode. Three plateaus are observed in the quasi-equilibrium open circuit potential curves, which are indicative of a mixed phase upon lithium-ion intercalation/deintercalation. The obtained diffusion coefficients tend to increase with increasing lithium concentration and exhibit an insignificant difference between charge and discharge conditions. This study reveals that the diffusion coefficient of graphite obtained with the GITT (1 × 10−11 cm2/s to 4 × 10−10 cm2/s) is in reasonable agreement with literature values obtained from electrochemical impedance spectroscopy. The GITT is comparatively simple and direct and therefore enables systematic measurements of ion intercalation/deintercalation diffusion coefficients for secondary ion battery materials.