| Stage-Dependent Volume Variation and Potential Behavior of Graphite Anodes with N/P Ratios |
|
Min Hyeok Oh, Kyou Bong Lee, Sung-Soo Kim |
|
Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea |
Correspondence:
Sung-Soo Kim,
Email: kimss@cnu.ac.kr
|
Received: 22 April 2026 • Accepted: 4 June 2026
*Min Hyeok Oh and Kyou Bong Lee contributed equally to this study as co-first authors. |
| Abstract |
|
In this study, a three-electrode full-cell combined with in situ dilatometry was used to investigate the effects of the Negative-to-Positive (N/P) ratio on the anode potential and thickness evolution of graphite anodes. Even under identical full-cell cut-off conditions, the anode potential varied with the N/P ratio, resulting in different lithiation depths. A lower N/P ratio enabled deeper lithiation and greater electrode expansion. To analyze this behavior, the state of charge (SoC) was expressed in terms of the LixC6 composition. As the N/P ratio decreased, the contribution of stage 1 (LiC6) increased, while that of the dilute region decreased. This reflects enhanced lithium insertion between graphene layers, which increases the interlayer spacing and thereby contributes to larger volume expansion. Furthermore, the increased fraction of stage 1 was associated with higher irreversible expansion, suggesting that deeper lithiation can increase the electrode-level expansion burden. These findings suggest that controlling the N/P ratio can be useful for regulating lithiation depth and stage-dependent expansion behavior, providing design considerations for graphite and Si–graphite composite anodes. |
| Keywords:
In-situ Dilatometry, Lithium-ion battery, Natural graphite, N/P ratio |
|
PDF Links
Full text via DOI
Download Citation
