Covalent Adaptable Network Enables Sustainable Polyethylene for Next-Generation Cable Insulation

Cross-linked polyethylene (XLPE) with favorable electrical and mechanical properties is a key component of high voltage power transmission. However, damages caused by strong electrical and high mechanical stresses tend to initiate structural degradation of insulating materials, which in severe cases can lead to catastrophic failure of equipment. The irreversible curing property of XLPE presents significant challenges in self-healing after damage and recycling after decommissioning. Herein, an innovative strategy is developed that utilizes Cu-catalyzed amination to synthesize functionalized polyethylene, combined with dynamic covalent chemistry to prepare tailorable covalent adaptable networks (CANs). Due to the exchange of dual dynamic covalent bonds, the prepared CANs exhibit excellent self-healing and recycling properties, with performance recovery efficiency close to 100% after mechanical and electrical damage. Furthermore, the ingeniously designed structure of CANs, which combines "strong" permanent cross-linking with "weak" dynamic cross-linking, achieves a higher toughness of 102.0 MJ m^-3 and excellent electrical insulation properties (electric field distortion rate of only 7% at 70 °C) than XLPE. This work promotes the environmental friendliness and long life of XLPE, paving the way for a new generation of sustainable cable insulation.