A FTO/MXene@PdTe2@TiO2//PANI composite for the development of light-responsive electrodes for solar-integrated hybrid supercapacitors.

The development of multifunctional electrodes capable of simultaneously harvesting solar energy and storing electrical charge is highly attractive for next-generation self-powered energy systems. Herein, we introduce a ternary MXene@PdTe2@TiO2 heterostructure as a multifunctional photo-electrochemical electrode, in which highly conductive MXene, broadband photoresponsive PdTe2, and semiconducting TiO2 are synergistically integrated to couple solar-energy harvesting with electrochemical charge storage. The distinctive ternary architecture promotes interfacial charge separation and transfer, facilitates ion diffusion, and accelerates faradaic reaction kinetics, enabling the construction of a photo-electrochemical hybrid asymmetric MXene@PdTe2@TiO2//PANI@AC supercapacitor. The resulting MXene@PdTe2@TiO2-electrode has a high power conversion efficiency (PCE) of 16%, a high value of fill factor (FF) of 87%, and a maximum open-circuit voltage (V oc) of 0.74 V. The obtained values of Schottky barrier height and ideality factor (Φ = 0.35, and n = 1.22) also prove the positive charge transfer dynamics and minimum ionic recombination loss. The MXene@PdTe2@TiO2//PANI@AC hybrid device offered the highest specific charge (Q s) of 279 C g-1, energy density of 45 Wh kg-1 at a power density of 2469.77 W kg-1, and it has a high retention of 98.36% over 10 000 cycles, indicating its good long-term stability of operation under solar illumination because of effective photogenerated electrons by the PdTe2-TiO2 synergy. Collectively, these findings indicate that MXene@PdTe2@TiO2//PANI@AC is a high-performance photoelectrochemical electrode that couples solar energy harvesting with improved electrochemical charge storage, providing a potential platform for next-generation solar-assisted and photo-rechargeable hybrid energy storage technologies.