Structural modulation of lithium metal-electrolyte interface with three-dimensional metallic interlayer for high-performance lithium metal batteries.

Jongchan Song,Hee-Tak Kim,Yun-Jung Kim,Jung-Ki Park,Hongkyung Lee

doi:10.1038/srep30830

Abstract

The use of lithium (Li) metal anodes has been reconsidered because of the necessity for a higher energy density in secondary batteries. However, Li metal anodes suffer from ‘dead’ Li formation and surface deactivation which consequently form a porous layer of redundant Li aggregates. In this work, a fibrous metal felt (FMF) as a three-dimensional conductive interlayer was introduced between the separator and the Li metal anode to improve the reversibility of the Li metal anode. The FMF can facilitate charge transfer in the porous layer, rendering it electrochemically more active. In addition, the FMF acted as a robust scaffold to accommodate Li deposits compactly in its interstitial sites. The FMF-integrated Li metal (FMF/Li) electrode operated with a small polarisation even at a current density of 10 mA cm−2, and it exhibited a seven times longer cycle-life than that of an FMF-free Li electrode in a symmetric cell configuration. A Li metal battery (LMB) using the FMF/Li electrode and a LiFePO4 electrode exhibited a two-fold increase in cycling stability compared with that of a bare Li metal electrode, demonstrating the practical effectiveness of this approach for high performance LMBs.

Highlights

Approaches include the manipulation of the Li dendrite growth behaviour by three-dimensional (3D) frameworks such as silica/silicon carbide (SiO2/SiC)-covered carbon fibre paper[30], polyaniline/carbon nanotube (PANI/CNT) composite buffer layer[31], nanostructured graphene framework32,33, 3D poly(acrylonitrile) fibre mat[34], fibrous Li/B (Li7B6) matrix[35] and hollow titanate (TiO2) nanotubes array[36]
We present a fibrous metal felt (FMF) as a 3D-conductive interlayer in order to enhance the reversibility of the Li metal electrode
The coulombic efficiency (CE) can be defined as the ratio of Li removed from the working electrode to that deposited on the working electrode during the same cycle

Summary

Introduction

Approaches include the manipulation of the Li dendrite growth behaviour by three-dimensional (3D) frameworks such as silica/silicon carbide (SiO2/SiC)-covered carbon fibre paper[30], polyaniline/carbon nanotube (PANI/CNT) composite buffer layer[31], nanostructured graphene framework32,33, 3D poly(acrylonitrile) fibre mat[34], fibrous Li/B (Li7B6) matrix[35] and hollow titanate (TiO2) nanotubes array[36]. To demonstrate the positive functions of the FMF for the reversibility of Li deposition/dissolution processes, a galvanostatic cycling test was carried out for a coin-type cell using the FMF as a working electrode and the Li metal electrode as a counter electrode, and the results were compared with those for a Cu|Li coin cell (Supplementary Fig. S1).

Results

Conclusion