From design to disposal: Fabrication of stable, burnable all-polymer thermoelectric modules for self-powered sensors

All-polymer thermoelectric (TE) modules have emerged as viable solutions for sustainable energy harvesting, particularly in low-power Internet of Things (IoT) applications. This study proposes a fully metal-free all-polymer TE module fabricated using poly(benzodifurandione) (PBFDO) as the n-type material and PEDOT:PSS as the p-type material. The anisotropic TE behavior of PBFDO was comprehensively evaluated by comparing its in-plane and through-plane properties. Unlike previous designs that incorporated metal or interfacial layers for electrical connections, the proposed module employs a direct lamination process, eliminating the need for metal electrodes while maintaining low interfacial resistance. Notably, the device exhibits excellent long-term stability, maintaining consistent interfacial resistance for more than a year. With a power density exceeding 30 μW/cm2 at 100 °C under natural convection, the proposed module can sustainably power Bluetooth low-energy sensors. In addition, it demonstrates thermal degradability at temperatures exceeding 400 °C, enabling its disposal as burnable waste. These findings highlight the viability of fully organic TE modules as sustainable and eco-friendly energy sources for IoT applications.