Anomalous high ionic conductivity of nanoporous β-Li3PS4

Abstract

Lithium-ion conducting solid electrolytes hold the promise for enabling high-energy battery chemistries and circumventing safety issues of conventional lithium batteries1-3. Achieving the combination of high ionic conductivity and broad electrochemical window in solid electrolytes is a grand challenge for the synthesis of battery materials. Herein we show an enhancement of room-temperature lithium-ion conductivity of 3 orders of magnitude by creating nanostructured Li3PS4. This material has a wide (5V) electrochemical window and superior chemical stability against lithium metal. The nanoporous structure of Li3PS4 reconciles two vital effects that enhance ionic conductivity: (1) The reduced dimension to nanometer-sized framework stabilizes the high conduction beta phase that occurs at elevated temperatures1,4; and (2) The high surface-to-bulk ratio of nanoporous β-Li3PS4 promotes surface conduction5,6. Manipulating the ionic conductivity of solid electrolytes has far-reaching implications for materials design and synthesis in a broad range of applications such as batteries, fuel-cells, sensors, photovoltaic systems, and so forth3,7.