Figure 2

(a and b) TEM images of NiCo₂S₄ nanosheets at different magnifications. (c) HRTEM image of NiCo₂S₄ nanosheets. (d) Representative EDX spectrum of NiCo₂S₄ nanosheets scratched from carbon cloth. HRTEM, high-resolution TEM; TEM, transmission electron microscopy; EDX, energy-dispersive X-ray spectroscopy.