A composite material blending ionogel with two-dimensional MXene nanosheets can continuously convert waste heat into electrical energy. Liquid ionic materials produce strong thermal voltages but normally stop generating current under constant heat because trapped ions cannot cross into metal wires. Mixing conductive nanosheets into the gel lets electrons tunnel across the gaps while heat separates the ions, sustaining a steady flow of current.
When heat touches one side of the generator, the ionic Soret effect drives mobile ions away from the warm side toward the cold side. This movement acts like a chemical battery creating internal electrical pressure across the solid gel. Electrons then hop through the narrow gaps between MXene nanosheets by quantum tunneling, passing directly through the material to the external electrodes. This paired movement of ions and electrons prevents charge from piling up and blocking current.
The research team built the mixed ion-electron thermoelectric generator by embedding MXene flakes inside an ionic gel network. During testing, the device produced a thermopower of 4.77 millivolts per kelvin. The system maintained a stable output voltage under a constant temperature gradient and continued supplying power for a very long time.
The authors report that this hybrid approach enables heat-to-electricity conversion under both steady and fluctuating temperature conditions. The resulting generator matches the steady-state performance of conventional electronic thermoelectric devices while retaining the high thermal voltages of ionic systems.