Ag₂Se Nanowire Fusion-Engineered Nylon Composite films: Boosting the Stability and Thermoelectric Efficiency in...

Near-room-temperature flexible thermoelectric (TE) generators (f-TEGs) can help resolve the energy supply problem of wearable electronic devices during long-term use. Due to their promising TE performance, Ag₂Se nanowires (NWs) are considered as credible candidates to fabricate flexible TE films and devices, but their "liquid-like" properties and loose connection between Ag₂Se NWs leads to instability and low electrical conductivity. Herein, we report an interwoven network structure in a Ag₂Se/nylon composite film via Ag₂Se NWs fusion under hot-pressing to enhance the mechanical flexibility and TE performance stability. The optimal film exhibits an ultrahigh room temperature (RT) power factor (PF) of ∼1864 μWm^1-K^-2 (average PF ∼ 2034 μWm^1-K^-2 over 300-400 K) and excellent performance stability (a negligible PF difference during 14 repeated tests). After 5000 repeated bending operations, the film shows only a 4% increase in electrical resistance, indicating excellent mechanical flexibility. An assembled 5-leg f-TEG produces an open-circuit voltage (V_oc) of ∼38 mV and a maximum output power of ∼6.7 μW at a temperature difference (ΔT) of 60 K (corresponding power density ∼ 84 Wm^2-). This work demonstrates that Ag₂Se NW fusion is conducive to both TE performance stability and flexibility of Ag₂SeNW-based flexible films and opens an avenue for applications in self-powered wearable electronic devices.