Abstract: PEG₆₀-polylactic acid (PLA₄₀)-CNT_0.6-X_(y) phase-change energy storage composites were prepared in this paper by physically hybridizing carbon nanotubes (CNT) with BN, Al₂O₃, and copper powder (Cu), respectively, to investigate the effects of nanoparticles with different structures on the shape stability and photovoltaic conversion efficiency of polyethylene glycol (PEG) based phase-change composites. The incorporation of Al₂O₃ and Cu nanofillers has a minor effect on the electrical conductivity of the PEG-PLA-CNT-X_(y) composites. However, the introduction of BN drastically reduces the electrical conductivity of the composites. When the mass ratio of BN reaches 40%, the electrical conductivity of the PEG₆₀-PLA₄₀-CNT_0.6-BN₍₄₀₎ composites is only 8.71×10⁻⁷ S/m, indicating obvious insulating properties. The spherical Al₂O₃ nanoparticles were found to be uniformly distributed inside the composites by SEM and EDS energy spectroscopy, and the thermal conductivity and enhancement factor ( \varPhi ) values of PEG₆₀-PLA₄₀-CNT_0.6-Al₂O₃₍₄₀₎ composites were as high as 5.81 W/(m·K) and 363.6%, respectively. Compared to the PEG₆₀-PLA₄₀-CNT_0.6 composites, the addition of Al₂O₃ improves the photothermal conversion efficiency ( \eta ), photo sensitive response rate, and current stability of PEG₆₀-PLA₄₀-CNT_0.6-Al₂O₃₍₄₀₎ composites, raising the value from 42.9% to 79.9%. Moreover, composite materials exhibit higher sensitivity to light, faster response time, smoother current change curves, and excellent photoelectric conversion performance.