<p>Ionic polymers are promising electrolyte materials but have inherent limitations when used alone. In this study, flexible network ionic polymer supports were prepared from a piperidinium bis(fluorosulfonyl)imide-based ionic monomer, n-butyl acrylate, and ethoxylated trimethylolpropane triacrylate (ETPTA). Composite electrolytes were fabricated by incorporating the organic ionic plastic crystal 1,2-bis(<i>N</i>-methylpiperidinium)ethane bis(fluorosulfonyl)imide and lithium bis(fluoro-sulfonyl)imide (LiFSI). The composite with a polymer-to-salt ratio of 7:3 and an OIPC-to-LiFSI ratio of 7:3 exhibited the highest ionic conductivity of 5.28 × 10⁻⁵ S&#xa0;cm⁻¹ at 30 °C, which is more than ten times higher than that of the polymer containing only LiFSI. The composites were thermally stable up to 200 °C and electrochemically stable up to 5.5 V. demonstrating that introducing OIPC into a network ionic polymer matrix enhances ionic conductivity while maintaining stability and flexibility of polymer electrolyte materials.</p> Graphical abstract <p>Ionic polymer composite electrolytes were prepared by incorporating network ionic polymer, organic ionic plastic crystal 1,2-bis(<i>N</i>-methylpiperidinium)ethane bis(fluorosulfonyl)imide and lithium bis(fluoro sulfonyl)imide (LiFSI)). One of the ionic composites with a polymer-to-salt ratio of 7:3 exhibits the highest ionic conductivity of 5.28 × 10⁻⁵ S&#xa0;cm⁻¹ at 30 °C. They are thermally stable up to 200 °C and electrochemical stable up to 5.5 V, and can be a good candidate for polymer electrolyte systems of lithium secondary batteries.</p>