Theoretical boundary and optimization methodology of contact-separation triboelectric nanogenerator

Triboelectric nanogenerators (TENGs) have exhibited great potential as the promising energy harvesters in recent decades. To obtain superior output performance, advances in materials science and engineering technology have been applied to promote the surface charge density and energy output. In this work, the mathematical derivations have been developed to derive the theoretical boundary under the air breakdown restriction for contact-separation mode TENGs. Through the optimization of limitation equations, mathematical relations were deduced between the output evaluation metrics and TENGs’ design including the structural and material factors. In addition, methodologies for output performance enhancement were proposed, from which an optimized model possessing 10 μm silicone rubber as the dielectric layer exhibits 2.85 mC/m² in surface charge density and 1.12 mJ in energy output under 2 cm separation distance. This work provides systematical analysis and comprehensive predicts for the theoretical boundary of TENGs’ capability, which gives guidance on the design and optimization for high-performance TENGs.