Open Access

REVIEW

Design Principles of Ultrathin Polymer-Based Electrolyte for Lithium-Metal Batteries

Xinyuan Shan^1,2, Yuan Wei¹, Jiayao Chen^1,*, Peng-Fei Cao^1,*

1 State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China
2 State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecule Science, Fudan University, Shanghai, 200438, China

* Corresponding Authors: Jiayao Chen. Email: ; Peng-Fei Cao. Email:

Journal of Polymer Materials 2025, 42(3), 571-586. https://doi.org/10.32604/jpm.2025.068907

Received 10 June 2025; Accepted 07 August 2025; Issue published 30 September 2025

Abstract

In recent years, ultrathin polymer-based electrolytes (UPEs) have emerged as a promising strategy to enhance the energy density of rechargeable batteries for wearable devices by minimizing electrolyte volume, demonstrating higher ionic conductance and lower internal resistance, and more compact battery stacking compared to conventional thick polymer-based electrolyte. This mini review systematically summarizes recent advances in ultrathin solid-state and gel-state electrolytes, focusing on their preparation strategies, advantages, and disadvantages, where the energy density, interfacial stability, mechanical properties, and ion-transport mechanisms are also analyzed for understanding the UPE application. Moreover, the challenges such as dendrite penetration and instability (thermal, chemical and interface), along with their solutions are also introduced through interfacial engineering, polymer matrix design, and fillers incorporation. Furthermore, for practical application, the demands of working current density, operating temperature and scale-up production are also illustrated. This mini review is hoped to spark insights into improving the energy density of batteries and ultimately bring us a step closer to realizing superior rechargeable batteries.

---

Keywords

---