Modeling, fast-prototyping and testing of a stacked-fin triboelectric module using biodegradable materials and scalable structural design

Energy harvesting involves converting environmental energy from common sources such as light, vibration, pressure, and temperature into a usable form, typically on a small scale for wearable embedded applications. Triboelectric nanogenerators (TENGs) convert mechanical energy such as wind, sea waves, machine vibrations, or human motion into electrical energy via contact electrification and electrostatic induction. This work focuses on triboelectric energy harvesting from low-frequency human motion using 3D-printable materials for wearable biomedical applications, particularly to extend battery life or enable batteryless operation in musculoskeletal monitoring and gait/balance. A novel 130 ×130 ×15.5 mm TENG design with stacked-fin architecture is proposed, which operates in sliding freestanding mode, offering scalability and miniaturization to meet specific application requirements. The design is developed using in-house analytical models and Fusion 3D tools, and is fabricated using Thermoplastic Polyurethane (TPU) in dielectric layers, non-conducting Polylactic Acid, and partially conducting Polylactic Acid - Graphite Composite (PLA-G). Developed analytical model has been correlated with prototype testing in realistic wearable environment. The experimental results highlight the need for scalable conducting layer and electrode design with lower electrical resistance in the next revision, as well as considerations for output impedance matching. The main outcome of the study is the verification of the feasibility of a rapid prototyping approach using predictive analytical model of a novel triboelectric structure for wearable sensing and energy harvesting applications that optimize cost and size by custom-scaling the power source.