Open Access

ARTICLE

Segmental Dynamics, Ion-Associated Relaxation, and Ion Transport in Cellulose-Based Gel Polymer Electrolytes Revealed by Broadband Dielectric Spectroscopy

Ruoxi Zhang¹, Rongzu Sun¹, Wei Zhou^2,*, Zhen Chen^1,*
1 Department of Applied Chemistry, School of Materials and Chemistry, Anhui Agricultural University, Hefei, China
2 School of Light Industry Science and Engineering, Beijing Technology and Business University, Beijing, China
* Corresponding Author: Wei Zhou. Email: ; Zhen Chen. Email:

Journal of Polymer Materials https://doi.org/10.32604/jpm.2026.087360

Received 15 June 2026; Accepted 14 September 2026; Published online 22 September 2026

Abstract

Cellulose-based gel polymer electrolytes (GPEs) are promising sustainable candidates for next-generation lithium batteries; however, the relationship between polymer dynamics and ion transport remains insufficiently understood. In this study, cellulose-based GPEs with varying lithium salt concentrations and crosslinking densities were systematically investigated using broadband dielectric spectroscopy, complemented by structural and thermal characterizations. Three dielectric relaxations including a secondary $\beta$ relaxation, a structural $\alpha$ relaxation arising from cooperative segmental motion of the cellulose network, and a slower near-Debye ${\alpha }^{\prime }$ relaxation were identified. Both the $\alpha$ and ${\alpha }^{\prime }$ processes follow Vogel–Fulcher–Tammann (VFT) behavior, indicating their strong coupling with the glassy dynamics of the polymer matrix. The ${\alpha }^{\prime }$ process is plausibly ascribed to orientational polarization of ion-associated species, such as transient ion pairs or small ionic aggregates coordinated with the cellulose network. The direct current conductivity of the samples was also found following VFT behavior. Notably, the conductivity relaxation time nearly coincides with the $\alpha$ relaxation time across the entire investigated temperature range for all compositions, suggesting that lithium-ion transport is predominantly governed by polymer segmental dynamics. The dielectric glass transition temperature and fragility index, derived from VFT analysis, exhibit marked dependencies on salt concentration and crosslinking density, whereas the calorimetric glass transition temperature remains virtually invariant. This work unveils a strongly coupled ion-transport mechanism and provides fundamental insights into the intricate interplay among polymer dynamics, ionic association, and charge transport in cellulose-based GPEs.

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Keywords

Gel polymer electrolyte; dielectric spectroscopy; lithium batteries; solid-state electrolyte; direct current conductivity; structural relaxation

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