Cactus‐Inspired Tip Interfaces Coupling Transient Thermorheology and Local Polarization Amplification for Efficient Pyroelectricity Energy Harvesting

Pyroelectric nanogenerators offer a promising approach for harvesting ubiquitous low‐grade environmental energy; however, their actual output remains constrained by slow temperature response rates and inefficient polarization dynamics under natural environmental temperature fluctuations. This paper reports a cactus spine‐inspired graphene/carbon nanotube electrode‐based pyroelectric nanogenerator (CGC‐PyNG). It employs a 3D graphene/carbon nanotube electrode with a conical array to synergistically amplify the thermal and electrical processes within a single interfacial structure. The biomimetic conical tip geometry synergistically enhances both the solar‐driven photothermal effect and wind‐induced convective cooling, significantly accelerating the transient temperature response rates. Crucially, the 3D electrode induces a highly localized tip‐enhanced electric field that actively modulates the pyroelectricity polarization dynamics, effectively lowering the dipole reversal energy barrier and boosting the polarization rate by 1.9 times. This pyroelectricity coupling amplification effect generates significantly enhanced pyroelectric signals. Under sunlight, CGC‐PyNG achieves instantaneous current peaks of 156 nA and open‐circuit voltages exceeding 200 V. When exposed to alternating solar radiation and airflow in outdoor environments, CGC‐PyNG can stably and continuously harvest energy, offering a broadly applicable strategy for the efficient utilization of low‐grade random environmental energy in self‐powered wearable and distributed electronic systems.