Triboelectric nanogenerators for wearable sensing applications: A system level analysis

Wearable sensing is a rapidly expanding research area with significant future potential and impact, encompassing lifestyle, sports & fitness and healthcare applications. The target of the next generation of wearable technologies is to be energy efficient, accurate, intelligent and integrate seamlessly with the body as a second skin. Triboelectric Nanogenerators (TENGs), which use static charging and electrostatic induction to convert body movements into electrical pulses, are envisioned as a key addition to next generation wearables due to their self-powered sensing and energy harvesting capabilities. TENGs offer high instantaneous electrical outputs, low cost, flexibility and comfort, presenting the potential for autonomous and maintenance free operation of wearable sensing applications. This paper provides a comprehensive review on the cutting-edge developments in TENG based wearable sensing systems. Herein, we present a holistic system level assessment where we analyse the sensing and power generation functions of the TENGs as well as the related power management, signal acquisition, decision making, connectivity and integration processes. The drawbacks and the most critical challenges of the existing technology are discussed, with perspectives on potential routes to overcome them.