Designed fabrication of MoS2 hollow structures with different geometries and the comparative investigation toward capacitive properties

Abstract

Hollow MoS₂ cubes and spheres were synthesized by a one-step hydrothermal method with the hard template method. The structure and morphology were characterized, and their electrochemical properties were studied. It is concluded that the specific capacitance of the hollow MoS₂ cubes (335.7 F g⁻¹) is higher than that of the hollow MoS₂ spheres (256.1 F g⁻¹). The symmetrical supercapacitors were assembled, and the results indicate that the specific capacitance of the device composed of hollow MoS₂ spheres (32.9 F g⁻¹) is slightly lower than that of the hollow MoS₂ cube (37.4 F g⁻¹) device. Furthermore, the symmetrical supercapacitor (MoS₂-cube//MoS₂-cube) provides a maximum energy density of 4.93 W h kg⁻¹, which is greater than that of the symmetrical capacitor (MoS₂-sphere//MoS₂-sphere, 3.65 W h kg⁻¹). This may indicate that hollow molybdenum disulfide cubes with substructures have more efficient charge transfer capabilities and better capacitance characteristics than hollow spheres. After 8000 cycles, the coulombic efficiency of the two symmetrical capacitors is close to 100%. The capacity retention of the MoS₂ sphere device (95.2%) is slightly higher than that of the MoS₂ cube device (90.1%). These results show that the pore structure, specific surface, and active site of MoS₂ with different hollow structures have a greater impact on its electrochemical properties.