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Updated: Oct 2, 2026
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Engineering interfacial molecular bridge APTES enhancing Li+ transport and interface stability in Al2O3/PVDF-HFP
Ao Li1, Lin Wu2, Pinghui Xu1
1Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China.
Abstract:
To address the demand for safe, high-energy-density lithium-metal batteries, we developed a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based composite electrolyte via an "interfacial molecular bridge" strategy. γ-aminopropyltriethoxysilane (APTES) molecules are covalently anchored onto Aluminum oxide (Al2O3) fillers, where the terminal NH2 groups act as Lewis base sites to immobilize bis(trifluoromethanesulfonyl)imide anion(TFSI-) anions, releasing free Li+ and boosting the transference number from 0.42 to 0.66. Concurrently, the uniformly dispersed fillers suppress PVDF-HFP crystallization, creating continuous amorphous pathways that deliver a high ionic conductivity of 7.02 × 10-4 S cm-1 with a low activation energy of 0.11 eV. A "more is less" effect of grafting density is revealed: insufficient grafting fails to inhibit agglomeration, while excessive silane forms an insulating polysiloxane barrier that degrades performance. The optimized electrolyte exhibits a wide electrochemical window (∼5.0 V), robust Li plating/stripping for over 1000 h at 0.1 mA cm-2, and stable cycling in LFP||Li full cells with 86.6% capacity retention over 500 cycles at 0.5C. This work establishes a surface-engineering paradigm for designing high-performance composite solid-state electrolytes.
