High-performance all-solid-state batteries enabled by salt bonding to perovskite in poly(ethylene oxide)

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Poly(ethylene oxide) (PEO)-based electrolytes are promising for solid-state lithium-metal batteries due to their compatibility with lithium anodes.
• However, low room-temperature ionic conductivity and lithium dendrite growth hinder their practical application in high-energy density batteries.

Purpose of the Study:

• To develop a flexible and low-cost composite electrolyte for all-solid-state Li-metal batteries.
• To enhance Li-ion conductivity and suppress lithium dendrite formation at the electrolyte-anode interface.

Main Methods:

• Preparation of a composite electrolyte by combining PEO with a perovskite material (Li3/8Sr7/16Ta3/4Zr1/4O3).
• Characterization of ionic conductivity and electrochemical performance of the composite electrolyte in symmetric Li/electrolyte/Li cells.
• Fabrication and testing of all-solid-state LiFePO4 and high-voltage LiNi0.8Mn0.1Co0.1O2 batteries using the composite electrolyte.

Main Results:

• The PEO/perovskite composite electrolyte exhibited Li-ion conductivities of 5.4 × 10^-5 S cm^-1 at 25 °C and 3.5 × 10^-4 S cm^-1 at 45 °C.
• A strong interaction between the bis-trifluoromethanesulfonimide (TFSI-) anion and the perovskite surface facilitated ion transport.
• Symmetric Li/electrolyte/Li cells demonstrated excellent cyclability at high current densities (up to 0.6 mA cm^-2).
• An in-situ formed solid electrolyte interphase layer effectively suppressed lithium dendrite growth.
• All-solid-state batteries showed impressive performance, including high Coulombic efficiencies, low overpotentials, and good cycling stability.

Conclusions:

• The developed PEO/perovskite composite electrolyte significantly enhances Li-ion transport and suppresses dendrite formation in solid-state Li-metal batteries.
• This composite electrolyte offers a promising pathway for realizing high-energy, safe, and stable all-solid-state lithium batteries.