Janus-Structured Composites for Energy Harvesting, Thermal Management, and Superior Triboelectric Output Performance

Abstract The intensifying global energy crisis and the steady advancement of the dual-carbon strategy have imposed increasingly stringent requirements on zero-energy temperature control technologies and renewable energy utilization systems across domains, such as building energy conservation, flexible electronics, and sensing. Herein, a multifunctional Janus-structured CA/PVDF/MXene (CPM) composite film was fabricated via electrospinning using a blended solution of cellulose acetate (CA) and polyvinylidene fluoride (PVDF) as an electrospinning precursor. The composite achieves subambient cooling of approximately 7.0 °C outdoors, demonstrating excellent daytime radiative cooling performance. The CPM-based triboelectric nanogenerator (TENG) exhibits outstanding electrical output, with an open-circuit voltage of 101.3 V, a short-circuit current of 3.9 μA, and a transferred charge of 34.9 nC. Moreover, the CPM-TENG shows excellent self-powered sensing capabilities, accurately detecting mechanical signals including human motion and handwriting traces, highlighting promising potential for applications in flexible wearable electronics. The composite possesses mechanical properties (200% enhancement in tensile strength), photothermal conversion capability (achieving a surface temperature of 64.6 °C under 0.8 W/cm2 irradiation), and Joule thermal response (reaching 156.4 °C at 6 V). This study provides a systematic design for multifunctional flexible electronic devices that integrate passive intelligent temperature regulation, mechanical energy harvesting, and high-sensitivity self-powered sensing.