Macro-microporous carbon with a three-dimensional channel skeleton derived from waste sunflower seed shells for sustainable room-temperature sodium sulfur batteries

Abstract Macro-microporous carbon (MMC), with a three-dimensional channel skeleton and co-doping of heteroatoms derived from waste sunflower seed shells, was synthesized through a facile chemical-activation process. The three-dimensional channel skeleton with a macroporous structure of the MMC formed an interwoven carbon network that effectively improved the electrical conductivity and facilitated the transfer of Na+ in the cell by allowing the electrolyte to permeate easily. The micropores (