Improving Ionic Conductivity with Bimodal-Sized Li7La3Zr2O12 Fillers for Composite Polymer Electrolytes

Yan Sun; Xiaowen Zhan; Jiazhi Hu; Yikai Wang; Shuang Gao; Yuhua Shen; Yang-Tse Cheng

doi:10.1021/acsami.8b21770

Improving Ionic Conductivity with Bimodal-Sized Li₇La₃Zr₂O₁₂ Fillers for Composite Polymer Electrolytes

ACS Appl Mater Interfaces. 2019 Apr 3;11(13):12467-12475. doi: 10.1021/acsami.8b21770. Epub 2019 Mar 20.

Authors

Yan Sun^{1

2}, Xiaowen Zhan², Jiazhi Hu², Yikai Wang², Shuang Gao², Yuhua Shen¹, Yang-Tse Cheng²

Affiliations

¹ College of Chemistry and Chemical Engineering, Lab for Clean Energy & Green Catalysis , Anhui University , Hefei 230601 , China.
² Department of Chemical and Materials Engineering , University of Kentucky , Lexington 40506 , United States.

PMID: 30855127
DOI: 10.1021/acsami.8b21770

Abstract

Ceramic-polymer composite electrolytes (CPEs) are being explored to achieve both high ionic conductivity and mechanical flexibility. Here, we show that, by incorporating 10 wt % (3 vol %) mixed-sized fillers of Li₇La₃Zr₂O₁₂ (LLZO) doped with Nb/Al, the room-temperature ionic conductivity of a polyvinylidene fluoride (PVDF)-LiClO₄-based composite can be as high as 2.6 × 10^-4 S/cm, which is 1 order of magnitude higher than that with nano- or micrometer-sized LLZO particles as fillers. The CPE also shows a high lithium-ion transference number of 0.682, a stable and low Li/CPE interfacial resistance, and good mechanical properties favorable for all-solid-state lithium-ion battery applications. X-ray photoelectron spectroscopy and Raman analysis demonstrate that the LLZO fillers of all sizes interact with PVDF and LiClO₄. High packing density (i.e., lower porosity) and long conducting pathways are believed responsible for the excellent performance of the composite electrolyte filled with mixed-sized ionically conducting ceramic particles.

Keywords: Li7La3Zr2O12; ceramic−polymer interactions; composite polymer electrolytes; ionic conductivity; lithium batteries.