<p>The degradation of electrical insulation is mainly attributed to local defects. Although incorporating organic small molecules into dielectric polymers promotes the insulation strength, accurate suppression of defect development is a long-term and formidable challenge. Here we utilize the adaptive charge capture methodology to achieve precise defect suppression, leading to a 123% increase in the initiation voltage of electrical trees in anthrone/cross-linked polyethylene, significantly outperforming existing dielectric polymers and polymer composites. A significant observation is the confinement of charge at the interface between the anode and cross-linked polyethylene in anthrone/cross-linked polyethylene, generating a reverse inherent electric field near the interface and reducing the internal electric field strength of cross-linked polyethylene by up to 18%. These findings not only open avenues for further exploration of materials for ultra-high voltage cables but also play a crucial role in the commercialization and practical application of organic semiconductors in insulation dielectrics.</p>