How does the resonance frequency of a TENG affect its energy harvesting efficiency?

The resonance frequency of a TENG significantly affects its energy harvesting efficiency because it determines the frequency at which the TENG can most effectively convert mechanical energy into electrical energy. Every mechanical system, including a TENG, has a natural frequency at which it vibrates with the greatest amplitude when subjected to an external force. This is its resonance frequency. When the frequency of the external mechanical energy source matches the TENG's resonance frequency, the TENG experiences maximum displacement and strain, leading to optimal triboelectric charge generation and energy output. Operating the TENG at its resonance frequency maximizes the energy transfer from the mechanical source to the electrical domain. If the operating frequency deviates significantly from the resonance frequency, the TENG's displacement and strain are reduced, resulting in lower energy harvesting efficiency. For example, if a TENG is designed to harvest energy from human walking, its resonance frequency should be tuned to match the typical frequency of human gait (around 1-3 Hz) to maximize energy harvesting efficiency. The resonance frequency of a TENG can be adjusted by changing its mass, stiffness, and damping characteristics through careful design and material selection.