Bicontinuous Ionogel Electrolyte with Conductive Nanochannels for Flexible Supercapacitors

Abstract

Ionogels with excellent mechanical performance and conductivity have been considered as ideal candidates for flexible ionotronics. However, current ionogels suffer from the well-known trade-off between mechanical strength and conductivity. Herein, we construct an ionogel with bicontinuous phase structures, a polymer-rich phase, and a solvent-rich phase. The synergy of the polymer-rich phase as an energy dissipation mechanism and the solvent-rich phase as a conductive nanochannel enables the resultant bicontinuous ionogel to show comprehensive properties, a tensile strength of 4.2 MPa, a toughness of 14.4 MJ/m³, a conductivity of 4.3 mS/cm, excellent self-healing capability, and reprocessability. Benefiting from the remarkable mechanical performance and high conductivity, the integrated supercapacitor achieves a high specific capacitance of 118 mF/cm² (at a current density of 0.2 mA/cm²) and a capacitance retention of up to 90% (1000 charge-discharge cycles). More significantly, the resultant supercapacitor retains outstanding electrochemical performance even after being subjected to various deformations and even under harsh conditions. This study provides a reliable strategy for developing a high-performance ionogel electrolyte and broadens its application in flexible ionotronics.