Anisotropic Boron‐Carbon Hetero‐Nanosheets for Ultrahigh Energy Density Supercapacitors

Two-dimensional (2D) boron nanosheet that exhibits high theoretical capacitance, around four times that of graphene, has become significant supercapacitor electrode. However, its bulk structure with low interlaminar conduction and porosity restricts the charge transfer, ion diffusion and energy density. Herein, we develop a new 2D hetero-nanosheet made of anisotropic boron-carbon nanosheets (ABCNs) by B-C chemical bonds via gas-phase exfoliation and condensation bottom-up strategy. The ABCNs are constructed into high flexible supercapacitor electrode by microfluidic electrospinning. Specially, the ABCNs electrode greatly promotes electrolyte ions smooth-migration and excessive-storage due to large interlayer conductivity, ionic pathways and accessible surfaces. The flexible supercapacitor delivers ultrahigh volumetric energy density of 167.05 mWh cm-3 and capacitance of 534.5 F cm-3. More profoundly, an actually wearable energy-sensor system is designed to stably monitor physiological signals. The findings can highlight the architecture of new 2D nanomaterials and progress of wearable applications.