Implantable multilayer interdigitated triboelectric nanogenerator with nano-micro fibrous membrane and embedded switch-controlled capacitor for neck motion energy harvesting

Implantable electronic devices are increasingly recognized as indispensable technologies for a future-oriented humanity. The challenge of power supply is widely recognized as a significant hurdle, requiring interdisciplinary research efforts for its resolution. In this work, a multilayer interdigitated triboelectric nanogenerator (MI-TENG) is introduced, enhancing electrical output by laminating multiple layers of an interdigitated electrode structure. This structure enables multiple electrical output peaks from a single sliding reciprocating motion. For the contact layer, an electrospun nano-micro fibrous poly (methyl methacrylate) membrane is employed, resulting in a sixfold increase in open-circuit voltage (V_OC) peak and an 8.2-fold increase in short-circuit current (I_SC) peak. Notably, the current output at the end of each operation is amplified by integrating an embedded switch-controlled capacitor into the MI-TENG. The I_SC peak reaches 1.51 mA, a 1454.7-fold increase compared to the original I_SC peak of 1.038 μA. The voltage is regulated at 2.55 V, and an instantaneous power density of 1.18 W/m² is achieved at 5 kΩ. The fabricated MI-TENG is applied in neck motion harvesting, where energy is scavenged from various movements on the sternohyoid region. Applications are extended beyond wearable electronics to implantable electronics in a porcine model, demonstrating high potential as a bioenergy harvesting electronic device through real-time energy storage and generation verification.