A Flexible Lithium-Ion-Conducting Membrane with Highly Loaded Titanium Oxide Nanoparticles to Promote Charge Transfer for Lithium-Air Battery

Si-Han Peng; Yen-Hsiang Yu; Hsin-Chun Lu; Shingjiang Jessie Lue

doi:10.3390/polym15102409

A Flexible Lithium-Ion-Conducting Membrane with Highly Loaded Titanium Oxide Nanoparticles to Promote Charge Transfer for Lithium-Air Battery

Polymers (Basel). 2023 May 22;15(10):2409. doi: 10.3390/polym15102409.

Authors

Si-Han Peng¹, Yen-Hsiang Yu¹, Hsin-Chun Lu¹, Shingjiang Jessie Lue^{1

2

3}

Affiliations

¹ Department of Chemical and Materials Engineering, Chang Gung University, Guishan District, Taoyuan City 333, Taiwan.
² Department of Orthopedics, Chang Gung Memorial Hospital, Linkou, Guishan District, Taoyuan City 333, Taiwan.
³ Department of Safety, Health and Environmental Engineering, Ming-Chi University of Technology, Taishan District, New Taipei City 243, Taiwan.

Abstract

In this research, we aim to investigate a flexible composite lithium-ion-conducting membrane (FC-LICM) consisting of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and titanium dioxide (TiO₂) nanoparticles with a TiO₂-rich configuration. PVDF-HFP was selected as the host polymer owing to its chemically compatible nature with lithium metal. TiO₂ (40-60 wt%) was incorporated into the polymer matrix, and the FC-LICM charge transfer resistance values (R_ct) were reduced by two-thirds (from 1609 Ω to 420 Ω) at the 50 wt% TiO₂ loading compared with the pristine PVDF-HFP. This improvement may be attributed to the electron transport properties enabled by the incorporation of semiconductive TiO₂. After being immersed in an electrolyte, the FC-LICM also exhibited a R_ct that was lower by 45% (from 141 to 76 Ω), suggesting enhanced ionic transfer upon the addition of TiO₂. The TiO₂ nanoparticles in the FC-LICM facilitated charge transfers for both electron transfer and ionic transport. The FC-LICM incorporated at an optimal load of 50 wt% TiO₂ was assembled into a hybrid electrolyte Li-air battery (HELAB). This battery was operated for 70 h with a cut-off capacity of 500 mAh g^-1 in a passive air-breathing mode under an atmosphere with high humidity. A 33% reduction in the overpotential of the HELAB was observed in comparison with using the bare polymer. The present work provides a simple FC-LICM approach for use in HELABs.

Keywords: charge transfer; flexible lithium-ion-conducting membrane; hybrid electrolyte lithium–air battery; solid polymer composite; titanium dioxide nanoparticles.

Abstract

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