An in Situ-Formed Mosaic Li7Sn3/LiF Interface Layer for High-Rate and Long-Life Garnet-Based Lithium Metal Batteries

Bingkun Hu, Wei Yu, Bingqing Xu, Xue Zhang, Ting Liu, Yang Shen, Yuan Hua Lin, Ce Wen Nan, Liangliang Li

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Garnet-type solid electrolytes are suitable for solid-state batteries with a lithium metal anode, but it is challenging to fabricate garnet-based lithium metal batteries with a long cycle life at high rates. This study demonstrates that a mosaic Li7Sn3/LiF interface layer formed in situ on the surface of garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZT) through the reaction between a SnF2 coating layer and a lithium metal enables stable, high-rate cycling for LLZT-based batteries. The interface layer possesses a nanomosaic structure of Li7Sn3 nanoparticles and surrounding LiF, enabling fast lithium-ion conduction. Meanwhile, ion insulating Li2CO3 on the surface of LLZT pellets is completely removed by SnF2 during the formation of the interface layer, which reduces the ion diffusion barrier from LLZT to the lithium anode. Benefiting from the advantageous interface layer, LiFePO4||SnF2-LLZT||Li cells show superior cycle performance over 200 cycles at 1 C (272 μA cm-2) with a capacity of 140.6 mAh g-1 (94.6% retention) at 30 °C. Even at 2 C, a capacity of 102.9 mAh g-1 remains after 200 cycles. This work provides an optimal interfacial structure to enhance lithium-ion migration between garnet electrolytes and a lithium metal and paves the way for developing high-performance solid-state batteries.

Original languageEnglish
Pages (from-to)34939-34947
Number of pages9
JournalACS Applied Materials and Interfaces
Volume11
Issue number38
DOIs
Publication statusPublished - 2019 Sep 25
Externally publishedYes

Keywords

  • Li metal anode
  • garnet
  • high rate
  • solid-state batteries
  • stannous fluoride

ASJC Scopus subject areas

  • Materials Science(all)

Fingerprint

Dive into the research topics of 'An in Situ-Formed Mosaic Li<sub>7</sub>Sn<sub>3</sub>/LiF Interface Layer for High-Rate and Long-Life Garnet-Based Lithium Metal Batteries'. Together they form a unique fingerprint.

Cite this