Title of Paper:High-Performance Solid Polymer Electrolytes Filled with Vertically Aligned 2D Materials

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Date of Publication:2019-04-18

Journal:ADVANCED FUNCTIONAL MATERIALS

Included Journals:SCIE、EI

Volume:29

Issue:16

ISSN No.:1616-301X

Key Words:2D materials; ionic conductivity; solid polymer electrolyte; solid state electrolyte; vertical alignment

Abstract:Solid state lithium metal batteries are the most promising next-generation power sources owing to their high energy density and safety. Solid polymer electrolytes (SPE) have gained wide attention due to the excellent flexibility, manufacturability, lightweight, and low-cost processing. However, fatal drawbacks of the SPE such as the insufficient ionic conductivity and Li+ transference number at room temperature restrict their practical application. Here vertically aligned 2D sheets are demonstrated as an advanced filler for SPE with enhanced ionic conductivity, Li+ transference number, mechanical modulus, and electrochemical stability, using vermiculite nanosheets as an example. The vertically aligned vermiculite sheets (VAVS), prepared by the temperature gradient freezing, provide aligned, continuous, run-through polymer-filler interfaces after infiltrating with polyethylene oxide (PEO)-based SPE. As a result, ionic conductivity as high as 1.89 x 10(-4) S cm(-1) at 25 degrees C is achieved with Li+ transference number close to 0.5. Along with their enhanced mechanical strength, Li vertical bar Li symmetric cells using VAVS-CSPE are stable over 1300 h with a low overpotential. LiFePO4 in all-solid-state lithium metal batteries with VAVS-CSPE could deliver a specific capacity of 167 mAh g(-1) at 0.1 C at 35 degrees C and 82% capacity retention after 200 cycles at 0.5 C.