Collapse‐Resistant Large‐Sized 2D Metal‐Organic‐Framework‐Derived Nitrogen‐Doped Porous Ultrathin Carbon Nanosheets for High‐Performance Supercapacitors

Abstract

Abstract Metal‐organic‐framework (MOF)‐derived two‐dimensional materials have attracted tremendous attention in energy storage, because of their unique layered structure and abundant active sites. However, the facile synthesis of carbon materials simultaneously having large‐sized, ultrathin‐layered nanosheets and ultrahigh specific surface area remains a challenge. In this work, we develop a simple carbon protection strategy for efficiently stabilizing the ultrathin carbon nanosheets against structure degradation. The optimized as‐prepared sample (UPZCNs‐K4) exhibits a flat morphology with a large size (ca. 10 μm), a thickness of 2.8 nm, high pore volume, and a high capacitance of 402 F g −1 at 1 A g −1 in 6.0 M KOH aqueous electrolyte. An assembled symmetric supercapacitor delivers 16.18 W h kg −1 and 21.89 W h kg −1 output in KOH aqueous solution and Na 2 SO 4 electrolytes, respectively. The excellent performances of the optimized sample can be attributed to the combination of ultrahigh specific surface area for ions storage and ultrathin structure with large size for a short ion diffusion distance. We believe this work will aid in designing ultrathin porous carbon nanosheets with new nanostructures toward energy‐related applications.