Functional guanine superstructures derived superior sodiophilic porous carbonaceous metamaterial for anodic-sodium-metal-free sodium metal batteries

Abstract

Metamaterials, owing to their engineered building blocks, are considered as easily functionalized composites with designed nano-properties, sparking widespread research interest. However, the scalable synthesis and programmatically derived metamaterials into the designed nano-to-macro functionalized structure still pose significant challenges. Here, we report a fast and scalable synthesized Sn-guanine superstructures derived 1D porous carbonaceous metamaterial frameworks (Sn-NCS) that self-assembled by atomic Sn doping high nitrogen content carbon nanosheets. Due to the unique bottom-up designed nano-to-macro functionalized structural characteristics, Sn-NCS exhibited superior sodiophilic property. Using density functional theory (DFT) analysis and in-situ/ex-situ experimental characterization, we reveal that Sn-NCS can not only provide abundant Sn-N4 functional sites to minimize sodium nucleation overpotential and favors a uniform Na nucleation, but also effectively guide sodium deposition within the self-assembled porosity framework of Sn-NCS along the surface of carbon nanosheets to accommodate the volume variation and stress fluctuations within the anode, even under the extremely high current density of 120 mA/cm² with a deposition/stripping capacity of 20 mAh/cm². Moreover, the fabricated anode-sodium-metal-free sodium metal batteries (ASM-free SMB), using Cu-Sn-NCS (Sn-NCS coated Cu foil with a mass loading of 0.1 mg/cm²) as anodic current collector, exhibit highlighted energy density and excellent cycling reliability.