Figure 4.

a) Comparison of CV curves of Mn₂O₃ nanoparticles, single‐, double‐, triple‐ and quadruple‐shelled Mn₂O₃ hollow microspheres at a scan rate of 20 mV s^–1. b) Specific capacitances of Mn₂O₃ nanoparticles, single‐, double‐, triple‐ and quadruple‐shelled Mn₂O₃ hollow microspheres at various scan rates. c) Comparison of galvanostatic charge/discharge curves of Mn₂O₃ nanoparticles, single‐, double‐, triple‐ and quadruple‐shelled Mn₂O₃ hollow microspheres at a current density of 1 A g^–1 in the voltage range of 0–0.45 V. d) Cyclic stability of Mn₂O₃ nanoparticles, single‐, double‐, triple‐ and quadruple‐shelled hollow microspheres for 2000 cycles at a current density of 1 A g^–1.