The urgent demand for sustainable energy solutions faces a critical bottleneck: proton exchange membranes (PEMs) in high-temperature fuel cells (HT-FCs) struggle with rapid conductivity loss under anhydrous conditions above 100°C. Commercial perfluorosulfonic acid membranes fail in low humidity, while phosphoric acid-doped alternatives suffer from acid leakage, limiting efficiency and durability in next-generation energy devices.
A research team led by Kun Chen from the South China University of Technology pioneered a comb-like crosslinked polymer-polyoxometalate (POM) nanocomposite, integrating polymer with superacidic phosphotungstic acid (PW) clusters. This innovation achieves unparalleled anhydrous proton conduction and mechanical robustness.
The team published their study in Polyoxometalate on September 26, 2025.
"Our design merges covalent crosslinking and supramolecular interactions to create a dual-functional architecture," explained Lu Liu, co-first and corresponding author at the South China Advanced Institute for Soft Matter Science and Technology. "poly(glycidyl methacrylate) (PGMA) acts as a molecular comb, rapidly binding amino-polyethylene glycol (PEG-BA) to form a stable network, while PW clusters serve as both proton highways and nano-reinforcers. This synergy overcomes the classic trade-off between conductivity and strength."
The self-assembly process enables precise control: PGMA and PEG-BA crosslink in solution, followed by PW incorporation to establish continuous proton pathways through hydrogen bonding and ionic interactions.
Mechanical and thermal performance data highlight the nanocomposite's resilience: optimized formulations like PP3-70 (low crosslinking ratio with 70% PW) deliver:
•Proton conductivity: 8.5 × 10−4 S·cm−1 at 130 °C.
•Mechanical strength: Young's modulus up to 18.1 MPa.
•Stability: Consistent operation over 160 hours, with thermal stability above 150 °C.
This platform not only advances HT-FCs but also opens avenues for solid-state batteries and ion-transport materials. As Liu notes, "Modular tuning of crosslinking density and PW loading creates a versatile toolbox for future energy technologies."
Other contributors include Kewen Fu, Pengcheng Cui, Xiaojin Yan, and Yingying Wang from South China Advanced Institute for Soft Matter Science and Technology and School of Emergent Soft Matter at South China University of Technology in Guangzhou, China.
This work was supported by National Natural Science Foundation of China (22101086) and Guangzhou Science and Technology Plan Project (2025A04J3974).
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