A novel bilayer heterogeneous poly(ionic liquid) electrolyte for high-performance flexible supercapacitors with ultraslow self-discharge

A novel bilayer heterogeneous poly(ionic liquid) electrolyte consisting of a polycation complex and a polyanion complex is designed for highly flexible supercapacitors, which exhibit a high working potential of 3.0 V, energy density of 33 W h kg −1 and a long self-discharge time of 23.2 h.