Environmentally friendly super-insulating material with three-dimensional nanoporous structure: A promising candidate for future gas insulated transmission lines and carbon sequestration.

• Environmentally friendly super-insulating material with 3D nanoporous structure. • High breakdown field strength of the material composited with atmospheric CO 2. • Novel insulation form and carbon sequestration capacity for the future GIL. • Theoretical calculation for a substantial improvement of breakdown field strength. Gas-insulated transmission lines (GILs) play a pivotal role in facilitating the future long-distance transmission of power generated by renewable energy. However, the extensive employment of gaseous SF 6 presents formidable obstacles to scaled application of GILs, due to its relatively low breakdown strength and substantial greenhouse effect. In this work, a fantastic phenomenon was discovered that the breakdown field strength of insulating gases can be significantly enhanced under the confinement of nanostructures, based on it, the starch/polyorganosiloxane biocomposite insulating dielectric (S/PBID) with three-dimensional nanoporous structure was designed and fabricated. Specifically, insulating gases (CO 2 , N 2 , SF 6) composite with S/PBID, the breakdown field strength is significantly improved by 744.44 %, 520.74 %, and 310.95 % compared to the original gases, respectively. The relative permittivity of S/PBID (<2) is considerably lower than that of most existing insulating materials. Theoretical analysis suggests that the nanopores within S/PBID restricts electron multiplication and transport processes at the lateral scale, leading to a substantial enhancement in gas breakdown field strength. The nanoporous material is expected to be composited with atmospheric CO 2 to overturn the conventional gas–solid composite insulation form of the GILs, thereby providing a novel insulation form of high-performance, environmental-friendly, and carbon sequestration. [ABSTRACT FROM AUTHOR]