Decoupling the Effect of Electrolyte Infiltration on the Intercalation of Alkali Metal Ions in Highly Oriented Pyrolytic Graphite

• Published in: Journal of the Electrochemical Society Vol. 170; no. 4; pp. 40531 - 40536
• Main Authors: Li, Zhi-Yuan, Yang, Le, Li, Na, Lyu, Siqi, Chen, Hao-Sen, Song, Wei-Li
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2023
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/accb6c

Diffusion coefficients of ion in graphitic materials are responsible for high-rate batteries. However, the complex electrochemical response presented a challenge to accurately measure the diffusion coefficient of alkali-metal ions in graphitic materials. Here we design a method to identify the diffusion coefficients of Li + and Na + in highly oriented pyrolytic graphite (HOPG) with and without presence of liquid electrolyte infiltration. The results reveal inherent high diffusivity of Li + in HOPG (∼10 −7 cm 2 ·s −1 ), as compared to HOPG with electrolyte infiltration (∼10 −8 cm 2 ·s −1 ), while Na + has almost no interlayer diffusion without solvent infiltration. The presence of electrolyte has different effect on the interlayer diffusion of Li + and Na + .