Synthesis of high-quality black phosphorus sponges for all-solid-state supercapacitors

Abstract

Black phosphorus (BP) sponges synthesized electrochemically from bulk BP crystals comprise ultrathin (less than 4.0 nm) and large (over tens of micrometers) BP nanosheets as the basic unit and the semi-connected nanosheets provide open channels. The general oxidation of BP can be prevented by well-chosen apparatus with tetrabutylphosphonium bromide as the electrolyte. The all-solid-state supercapacitor constructed with BP sponge as the electrode material exhibits a high capacitance of 80 F g⁻¹ at 10 mV s⁻¹, which is much higher than those of bulk BP crystals and BP nanosheets. The BP sponges thus have great potential in energy storage applications. Furthermore, the modified electrochemical method provides the possibility for the high-quality exfoliation of other two-dimensional layered crystals to three-dimensional architectures.