Garnet‐Polymer Composite Electrolytes with High Li+ Conductivity and Transference Number via Well‐Fused Grain Boundaries in Microporous Frameworks

• Published in: ChemElectroChem Vol. 7; no. 11; pp. 2389 - 2394
• Main Authors: Peng, Xiang, Huang, Kai, Song, Shipai, Wu, Fang, Xiang, Yong, Zhang, Xiaokun
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 02.06.2020
• Subjects: ceramic framework; Chemical properties; composite electrolyte; Electrolytes; Electrolytic cells; Grain boundaries; Ion currents; ionic conductivity; Lithium; Lithium batteries; Optimization; Polymer matrix composites; Polymers; transference number; well-fused grain boundary
• ISSN: 2196-0216; 2196-0216
• DOI: 10.1002/celc.202000202

A garnet‐polymer composite electrolyte with high Li+ conductivity and transference number is developed using microporous Li6.4La3Zr1.4Ta0.6O12 (LLZTO) framework as the matrix. The LLZTO framework, fabricated by a template‐assisted gel‐casting process, possesses micron‐sized grains and well‐fused grain boundaries, eliminating the low‐conductive bottleneck at the interfaces between the ceramic blocks, and providing conductive and continuous networks for Li+ transport. As a result, the garnet‐polymer composite electrolyte displays a high ionic conductivity (2.61×10−4 S cm−1 at 25 °C), an ultrahigh Li+ transference number of 0.71, as well as excellent thermal, structural, and electrochemical stabilities. Benefiting from the desired physical and chemical properties, the presented composite electrolyte enables a Li−Li cell to be cycled for more than 600 h at 25 °C. In addition, the integrated LiFePO4/CPCE/Li cells also show excellent cycling stability with a specific capacity of 133.2 mAh g−1 after 100 cycles under 50 °C. This study demonstrates a significant optimization on the microstructure of composite electrolytes that can be utilized for all‐solid‐state lithium batteries. Continuous paths: We demonstrated a garnet‐polymer composite electrolyte exhibiting excellent Li+ conductivity and transference number, by applying a microporous Li6.4La3Zr1.4Ta0.6O12 (LLZTO) framework with well‐fused grain boundary