The significant opportunity to capture readily accessible high-entropy mechanical energy using triboelectric nanogenerators (TENGs) for powering millions of IoT-enabled wearable devices has garnered considerable interest in recent years. TENG-based self-powered sensors have generated much interest owing to their lightweight, inexpensive, flexible, biocompatible, and battery-free characteristics. However, these devices still face several challenges, including high internal impedance, low frequency operation, slow capacitor charging, and low efficiency due to the unavailability of accurate modeling and design. In this study, we present a novel approach to optimize the performance of interdigitated electrode array-based TENGs, operating in free-standing mode (IDA-FTENG) by introducing a gap-to-width ratio (GWR) relationship for the electrodes and its impact on the charge regeneration effect. We investigate the dependence of the charge regeneration effect on GWRs and the number of electrode pairs needed to enhance the performance of IDA-FTENGs, employing a rapid and industrially scalable laser scribing process for its fabrication.

This research primarily focuses on a comprehensive investigation of the effect of the charge regeneration process on enhancing the output performance of the IDA-FTENGs. This guides the derivation of the equivalent circuit of the IDA-FTENG in SPICE for the first time. Subsequently, this study demonstrates the achievement of highly efficient IDA-FTENG, characterized by an optimum matching resistance in the order of kΩ ( 95% reduction), and a 450 times faster capacitor charging process due to the 100 times increase in inherent frequency, enabling it to interface with the Internet of Things (IoT). An optimized device, featuring a maximum of 34 interdigitated electrode grids, demonstrates an open-circuit voltage of 800 V, a current density of 25 mA/m², and a more than 100-fold increase in power density compared to conventional single-electrode-pair TENGs (SEP-TENGs).

Furthermore, an IDA-FTENG incorporating up to 114 interdigitated electrode grids is projected to achieve a power density enhancement exceeding three orders of magnitude, reaching performance levels comparable to those of contemporary solar cells when optimally engineered. We showcase the applicability of the proposed IDA-FTENG devices as self-powered sensors in building an IoT-enabled smart home, remote human activity tracking, and a total self-powered identity verification system.