Indexed by:Journal Papers

Date of Publication:2020-08-15

Journal:CHEMICAL ENGINEERING JOURNAL

Included Journals:SCIE

Volume:394

ISSN No.:1385-8947

Key Words:Solid polymer electrolyte; Semi closed coordination; Theoretical calculation; In-situ polymerization; Lithium battery

Abstract:Low ionic conductivity and lithium ion transference number (t(Li+)) of solid polymer electrolytes (SPEs) preclude their practical implementation. Adjusting the coordination mode of the lithium ions and the polymer functional groups for improving the performance of SPEs is a great challenge. Herein, a combination of the density functional theory calculations and the molecular dynamics simulations is used to study the coordination structure of the lithium ion and its diffusion property in SPEs, demonstrating that a semi closed O-Li+ coordination mode in the poly ether/carbonate electrolyte with shorter ether chains leads to free lithium migration. Based on the theoretical calculations, the synthesized SPE realizes an excellent conductivity of 2.97 x 10(-4) S cm(-1) at 30 degrees C and a high t(Li+) of 0.78, accompanying with good electrochemical stability. In-situ polymerization is introduced to fabricate the solid-state battery, ameliorating the interface of the electrode and SPE. A solid-state LiFePO4/Li battery demonstrates superior rate capacity and cycling durability (95% capacity retention over 100 cycles) at elevated temperature. In addition, the performance of the battery with high voltage cathode is also evaluated at ambient temperature, maintaining respectable rate capability and cycling ability. The semi closed SPE with loose coordination is a competitive stratagem for improving the performance of solid-state batteries in the future.
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