Polycationic strategy and nanofiller synergy endow the dual network ionic liquid gel with excellent thermoelectric and mechanical properties

Ionic liquid gels require a high ionic concentration load to achieve high thermoelectric performance, which creates a “trade-off” between thermoelectric performance, operational stability, and mechanical properties. To address this challenge, a novel dual network gel integrating polycationic strategy and nanofiller reinforcement is proposed. The cations of 1-ethyl-3-vinylimidazolium dicyanamide undergo polymerization, which enhance Seebeck coefficient and effectively address ion leakage and poor mechanical performance. The incorporation of of SiO₂, modified graphene (mG), and Ti₃C₂T_x reduce crystallinity, strengthen interfacial phonon scattering, and introduce extensive hydrogen bonding, thereby improving both thermoelectric and mechanical performance. The novel gel achieves a giant Seebeck coefficient of 26.8 mV·K⁻¹(at 20 °C, 60 % relative humidity). Moreover, it exhibits remarkable stability indicated by stable performance during 5000 cycles, the stable dimensionless figure of merit (ZT) is 3.19 times as single network gel. The highly efficient stress dissipation network contributes to record-breaking mechanical properties, with a tensile strength of 14.3 MPa and an elongation of 535.7 %. Furthermore, the gel demonstrates enhanced flame resistance and anti-bacterial properties and is successfully applied in self-powered respiratory monitoring. This cationic self-polymerized modification strategy, combined with steric hindrance, phonon scattering and hydrogen bond reinforcement, provides a novel way for developing high performance ionic liquid gels.