Mechanical Interlocking Modulated (BiSb) ₂ Te ₃ /CNT Flexible Films: Synergistic Improvement of Thermoelectric and Mechanical Properties

Conventional carbon nanotubes (CNTs) and their composites struggle to simultaneously enhance thermoelectric (TE) and mechanical properties due to complex processing and interfacial issues that hinder practical applications. Here, a composite flexible film (BST/CNT) is prepared through in situ composite and vacuum hot‐pressing. CNT networks prepared by chemical vapor deposition are embedded within the (BiSb) 2 Te 3 (BST) matrix via an interfacial mechanical interlocking mechanism, constructing a composite structure characterized by “micro‐scale rigidity and macro‐scale flexibility”. The composite film demonstrates a significantly enhanced Seebeck coefficient of 105.7 µV K −1 alongside a high tensile strength of 204.3 MPa, achieving a synergistic enhancement in both TE and mechanical properties. In addition, the electrical transport performance of the film shows no significant degradation after 10 000 bending cycles, demonstrating bending stability. The 6‐legged flexible TE generator (F‐TEG) based on these films achieves a maximum output power of 0.36 µW at ΔT = 17.6 K. The film device worn on the forearm generates 1.13 mV with a 2.6 °C ΔT between skin and environment. Simultaneously, the composite films possess temperature sensing performance. This study provides feasible guidance for the design and development of CNT‐based flexible composite TE materials.