Interface Properties between Lithium Metal and a Composite Polymer Electrolyte of PEO18Li(CF3SO2)2N-Tetraethylene Glycol Dimethyl Ether.

Hui Wang,Yasuo Takeda,Dongmin Im,Dongjoon Lee,Masaki Matsui,Nobuyuki Imanishi,Osamu Yamamoto

doi:10.3390/membranes3040298

Hui Wang, Yasuo Takeda + Show 5 more

Open Access

https://doi.org/10.3390/membranes3040298

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Journal: Membranes	Publication Date: Oct 25, 2013
Citations: 65	License type: CC BY 3.0

Affiliation: Mie University, Samsung (South Korea)

Abstract

The electrochemical properties of a composite solid polymer electrolyte, consisting of poly(ethylene oxide) (PEO)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME) was examined as a protective layer between lithium metal and a water-stable lithium ion-conducting glass ceramic of Li1+x+y(Ti,Ge)2−xAlxP3−ySiyO12 (LTAP). The lithium ion conductivity and salt diffusion coefficient of PEO18LiTFSI were dramatically enhanced by the addition of TEGDME. The water-stable lithium electrode with PEO18LiTFSI-2TEGDME, as the protective layer, exhibited a low and stable electrode resistance of 85 Ω·cm2 at 60 °C, after 28 days, and low overpotentials of 0.3 V for lithium plating and 0.4 V for lithium stripping at 4.0 mA·cm−2 and 60 °C. A Li/PEO18LiTFSI-2TEGDME/LTAP/saturated LiCl aqueous solution/Pt, air cell showed excellent cyclability up to 100 cycles at 2.0 mAh·cm−2.

Highlights

Aqueous lithium-air batteries have been considered as a promising electrochemical energy storage system for electric vehicles
In our previous studies [6,7,8], we have reported that the interface resistance between lithium metal and polymer electrolytes in a water-stable lithium electrode (WSLE) is the dominant part of the cell resistance and an important factor in initiating lithium dendrite formation
We have previously reported an increase in the lithium ion transport number and decreases in the interface resistance of the lithium metal and polymer electrolyte by the addition of poly(ethylene glycol) dimethyl ether (PEGDME) to PEO18LiTFSI, where the mean molecular weight of PEGDME was 500 [14]

Summary

Introduction

Aqueous lithium-air batteries have been considered as a promising electrochemical energy storage system for electric vehicles. In our previous studies [6,7,8], we have reported that the interface resistance between lithium metal and polymer electrolytes in a WSLE is the dominant part of the cell resistance and an important factor in initiating lithium dendrite formation. The addition of low-molecular weight plasticizers to the PEO-based electrolyte is expected to improve the interface properties between lithium metal and the polymer electrolyte, and enhance the lithium ion transport number of the polymer electrolyte. We have previously reported an increase in the lithium ion transport number and decreases in the interface resistance of the lithium metal and polymer electrolyte by the addition of PEGDME to PEO18LiTFSI, where the mean molecular weight of PEGDME was 500 [14]. Li/PEO18LiTFSI-2TEGDME/LTAP/saturated LiCl aqueous solution/Pt, air cell is evaluated at 60 °C

Evaluation of CPEs

Electrochemical Performance of WSLEs

Experimental Section

Conclusions