Enhancing mechanical-to-charge conversion in triboelectric nanogenerators

Abstract

Triboelectric nanogenerators (TENGs) hold transformative promise for renewable energy harvesting and as power sources for the Internet of Things. However, a key challenge remains in concurrently enhancing their output energy and energy conversion efficiency, especially at high triboelectric charge densities. Here, our study reveals that increased frictional heat and electrostatic force at elevated charge densities lead to greater energy dissipations, thereby limiting efficiency improvements. To address this issue, we introduce a novel metric, the mechanical-to-charge conversion factor (f_M–Q), which quantitatively correlates surface charge density with friction force. This enables simultaneous assessment and optimization of output energy and energy conversion efficiency. Assisted by strategic material selection and interfacial lubrication, this synergy elevates f_M–Q by 7.8-fold, achieving a remarkable 17-fold enhancement in energy conversion efficiency and a record-breaking energy density of 11.9 J m⁻² cycle⁻¹. This work provides new insights into advancing practical triboelectric technologies with benefits of both performance and efficiency.