Distribution and Transport of Lithium Ions at Interfaces between Graphite and Carboxymethyl Celluloses

Authors

• Zijun Huang, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
• Zhenying Zheng, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
• Huawei Cao, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China; Shenzhen Haodyne Technology Co., Shenzhen, China.
• Jian Wang, Shenzhen Haodyne Technology Co., Shenzhen, China.
• Qingfeng Zhang, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.Follow
• Shengli Chen, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.Follow

Document Type

Article

Corresponding Author(s)

Qingfeng Zhang(zhangqf@whu.edu.cn);
Shengli Chen(slchen@whu.edu.cn)

Abstract

Carboxymethyl cellulose (CMC) is a water-processable binder widely used for graphite anodes. However, a microscopic understanding of why the identity of CMC counterions (Li⁺/Na⁺/K⁺) strongly affects electrode performance remains limited. Here, molecular dynamics (MD) simulations were used to track Li⁺ transport accessibility across electrolyte/CMC/graphite three-phase interfaces, comparing pure CMC-Li, CMC-Na, CMC-K, and mixed-counterion CMC binders. We find that CMC-Li sustains a continuous Li⁺ transport pathway from the electrolyte through the binder phase toward graphite. In contrast, in CMC-Na and CMC-K, Na⁺/K⁺ preferentially enrich at the graphite/binder interface, forming a cation-enriched interfacial layer which reduces Li⁺ accessibility to graphite. Partial replacement of Na⁺/K⁺ in CMC-Na and CMC-K with Li⁺ weakens this interfacial blocking effect and increases Li⁺ accessibility. Furthermore, a stage-resolved kinetic analysis visualizes the progressive suppression of  Li⁺ crossing the binder phase upon the barrier layer formation. These results provide a microscopic rationale for the experimentally observed performance advantage of CMC-Li over CMC-Na and CMC-K binders.

Graphical Abstract

Keywords

carboxymethyl cellulose binder, graphite anode, binder counterions, interfacial ion transport, cation-enriched interfacial barrier

DOI

10.61558/2993-074X.3611

Online Date

4-9-2026

Recommended Citation

Zijun Huang, Zhenying Zheng, Huawei Cao, Jian Wang, Qingfeng Zhang, Shengli Chen. Distribution and Transport of Lithium Ions at Interfaces between Graphite and Carboxymethyl Celluloses[J]. Journal of Electrochemistry, doi: 10.61558/2993-074X.3611.