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Anomalous High Ionic Conductivity of Nanoporous β‑Li3PS4

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journal contribution
posted on 23.01.2013, 00:00 by Zengcai Liu, Wujun Fu, E. Andrew Payzant, Xiang Yu, Zili Wu, Nancy J. Dudney, Jim Kiggans, Kunlun Hong, Adam J. Rondinone, Chengdu Liang
Lithium-ion-conducting solid electrolytes hold promise for enabling high-energy battery chemistries and circumventing safety issues of conventional lithium batteries. Achieving the combination of high ionic conductivity and a broad electrochemical window in solid electrolytes is a grand challenge for the synthesis of battery materials. Herein we show an enhancement of the room-temperature lithium-ion conductivity by 3 orders of magnitude through the creation of nanostructured Li3PS4. This material has a wide electrochemical window (5 V) and superior chemical stability against lithium metal. The nanoporous structure of Li3PS4 reconciles two vital effects that enhance the ionic conductivity: (1) the reduction of the dimensions to a nanometer-sized framework stabilizes the high-conduction β phase that occurs at elevated temperatures, and (2) the high surface-to-bulk ratio of nanoporous β-Li3PS4 promotes surface conduction. Manipulating the ionic conductivity of solid electrolytes has far-reaching implications for materials design and synthesis in a broad range of applications, including batteries, fuel cells, sensors, photovoltaic systems, and so forth.