Enhanced energy storage properties of red phosphorus/black phosphorus hybrid nanostructures

Abstract

The systematic investigation of the synthesis and characterisation of black phosphorus (BP) and red phosphorus (RP) hybrids was conducted to delve into their structural, morphological, and electrochemical properties. The phase transformation of amorphous RP to crystalline orthorhombic BP was achieved through a solvothermal approach, as confirmed by X-ray diffraction (XRD) and Raman spectroscopy. A complete phase transition was observed at 200 °C, with lattice parameters measured as a = 3.311 Å, b = 10.421 Å, and c = 4.373 Å. Additionally, Raman analysis identified characteristic BP vibrational modes at 361.62, 443.22, and 468.56 cm⁻¹. The crystalline nature of BP was confirmed through transmission electron microscopy (TEM) and selected area electron diffraction (SAED), revealing lattice fringes that correspond to the (111), (151) and (060) planes with a spacing of 0.245 nm, 0.166 nm and 0.176 nm. The analyses conducted through SEM and EDX demonstrated a layered structure devoid of impurities. The BET surface area analysis indicated a notable enhancement for the BP/RP hybrid, measuring 29.30 m² g⁻¹, in contrast to pristine BP at 16.27 m² g⁻¹ and RP at 3.86 m² g⁻¹. The electrochemical characterisation revealed the exceptional pseudocapacitive performance of the BP/RP hybrid, attaining a high specific capacitance of 87 F g⁻¹ at 0.5 A g⁻¹, surpassing values documented for comparable systems.