Flexoelectricity and ion transport synergy for high efficient energy conversion.

Ion transport is a fundamental process governing biological functions and energy conversion in electrochemical systems, but breaking through the efficiency limitations of these systems remains a challenge. Here, we report an ion transport mechanism in electrolytes driven by flexoelectricity of a carbon nanotube-filled porous polydimethylsiloxane composite. Because of the synergistic effect of flexoelectricity and ion transport, the efficiency of converting the total mechanical work into electrical energy reaches 6.54%, and the net energy conversion efficiency without the reversible elastic deformation energy being reckoned reaches 28.81%. The mass-specific and deformability-specific current of polydimethylsiloxane is enhanced by 1,000,000 times compared to that of solid truncated pyramid polydimethylsiloxane in air. The mass-specific electrical energy per unit stress is over 10 times that of the reported nanogenerators, and the performance remains stable for 10,000,000 cycles. Compressing 1.02 gram of the material once can generate enough electricity to light 800 light-emitting diodes. Our work provides a practical route for compliant and low-cost energy converting devices for applications in sensing, energy harvesting, and biosignaling.