A new organic–inorganic hybrid electrolyte based on polyacrylonitrile, polyether diamine and alkoxysilanes for lithium ion batteries: synthesis, structural properties, and electrochemical characterization

Abstract

A new type of organic–inorganic hybrid polymer electrolyte based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly-(propylene glycol)bis(2-aminopropyl ether), polyacrylonitrile (PAN), 3-(glycidyloxypropyl)trimethoxysilane (GLYMO) and 3-(aminopropyl)trimethoxysilane (APTMS) complexed with LiClO₄ via the co-condensation of organosilicas was synthesized. The structural and electrochemical properties of the materials were systematically investigated by a variety of techniques including differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), multinuclear (¹³C, ²⁹Si, ⁷Li) solid-state NMR, AC impedance, linear sweep voltammetry (LSV) and charge–discharge measurement. A maximum ionic conductivity value of 7.4 × 10⁻⁵ S cm⁻¹ at 30 °C and 4.6 × 10⁻⁴ S cm⁻¹ at 80 °C is achieved for the solid hybrid electrolyte. The ⁷Li NMR measurements reveal the strong correlation of the lithium cation and the polymer matrix, and the presence of two lithium local environments. After swelling in an electrolyte solvent, the plasticized hybrid membrane exhibited a maximum ionic conductivity of 6.4 × 10⁻³ S cm⁻¹ at 30 °C. The good value of the electrochemical stability window (∼4.5 V) makes the plasticized hybrid electrolyte membrane promising for electrochemical device applications. The preliminary lithium ion battery testing shows an initial discharge capacity value of 123 mA h g⁻¹ and a good cycling performance with the plasticized hybrid electrolyte.