Suppression of Lithium Dendrite Formation by Using LAGP-PEO (LiTFSI) Composite Solid Electrolyte and Lithium Metal Anode Modified by PEO (LiTFSI) in All-Solid-State Lithium Batteries

Chunhua Wang; Yifu Yang; Xingjiang Liu; Hai Zhong; Han Xu; Zhibin Xu; Huixia Shao; Fei Ding

doi:10.1021/acsami.7b00336

Suppression of Lithium Dendrite Formation by Using LAGP-PEO (LiTFSI) Composite Solid Electrolyte and Lithium Metal Anode Modified by PEO (LiTFSI) in All-Solid-State Lithium Batteries

ACS Appl Mater Interfaces. 2017 Apr 19;9(15):13694-13702. doi: 10.1021/acsami.7b00336. Epub 2017 Apr 7.

Authors

Chunhua Wang¹, Yifu Yang¹, Xingjiang Liu², Hai Zhong², Han Xu², Zhibin Xu², Huixia Shao¹, Fei Ding²

Affiliations

¹ College of Chemistry and Molecular Sciences, Wuhan University , Wuhan 430072, P.R. China.
² National Key Lab of Power Sources, Tianjin Institute of Power Sources , Tianjin 300384, P.R. China.

PMID: 28334524
DOI: 10.1021/acsami.7b00336

Abstract

The formation of lithium dendrites is suppressed using a Li_1.5Al_0.5Ge_1.5(PO₄)₃-poly(ethylene oxide) (LAGP-PEO) composite solid electrolyte and a PEO (lithium bis(trifluoromethane)sulfonimide) [PEO (LiTFSI)]-modified lithium metal anode in all-solid-state lithium batteries. The effects on the anode performance based on the PEO content in the composite solid electrolyte and the molecular weight of PEO used to modify the Li anode are studied. The structure, surface morphology, and stability of the composite solid electrolyte are examined by X-ray diffraction spectroscopy, scanning electron microscopy, and electrochemical tests. Results show that the presence of a PEO-500000(LiTFSI) film on a Li anode results in good mechanical properties and satisfactory interface contact features. The film can also prevent Li from reacting with LAGP. Furthermore, the formation of lithium dendrites can be effectively inhibited as the composite solid electrolyte is combined with the PEO film on the Li anode. The ratio of PEO in the composite solid electrolyte can be reduced to a low level of 1 wt %. PEO remains stable even at a high potential of 5.12 V (vs Li/Li⁺). The assembled Li-PEO (LiTFSI)/LAGP-PEO/LiMn_0.8Fe_0.2PO₄ all-solid-state cell can deliver an initial discharge capacity of 160.8 mAh g^-1 and exhibit good cycling stability and rate performance at 50 °C.

Keywords: PEO (LiTFSI); all-solid-state lithium battery; composite solid electrolyte; lithium dendrites; lithium metal anode.