Dielectric polymers are ubiquitous as electrical insulation in electrical power systems and electronic devices. Electrical treeing is typically regarded as an irreversible degradation process of dielectric polymers subjected to high electric stresses, which significantly limits their lifespan and endangers the reliability of electronics and electrical power systems. Here, we report self-healing polymers consisting of microcapsules that are capable of completely restoring the dielectric properties as a direct response to electrical tree degradation. We design the microcapsules with a relatively higher dielectric constant than polymer matrix to guide the propagation of electrical trees. The electroluminescence generated in situ during electrical treeing of polymers triggers crosslinking of the healing agents released from the capsules to repair the electrically damaged areas under ambient conditions. Notably, the breakdown strength of the mended region is largely enhanced upon healing, which was initiated at different locations. The integration of autonomous healing capability into dielectric materials opens new avenues to smart polymers for electronics and energy applications.

介电聚合物在电力系统和电子设备中普遍用作电绝缘。电树通常被认为是承受高电应力的介电聚合物的不可逆降解过程，这大大限制了它们的寿命并危及电子和电力系统的可靠性。在这里，我们报道了由微胶囊组成的自修复聚合物，这些微胶囊能够完全恢复介电特性，从而直接响应电树的降解。我们设计的微胶囊具有比聚合物基质更高的介电常数，以指导电树的传播。原位产生的电致发光在聚合物的电树化过程中，触发从胶囊释放的愈合剂的交联以修复环境条件下的电损伤区域。值得注意的是，修复区域的断裂强度在愈合时大大增强，这是在不同位置开始的。将自主修复功能集成到介电材料中，为电子和能源应用中的智能聚合物开辟了新途径。