LAUSR

Er-doped α-MnO2 (Er/α-MnO2) microspheres were successfully synthesized via a chemical process. The various techniques were used to investigate the crystal structures, morphologies, valence states, and electrochemical performances of the as-prepared materials. The results showed that Er can be doped into the lattice of α-MnO2 as Er3+ to distinctly affect the structure of α-MnO2. The as-obtained Er(1.5 at.%)/α-MnO2 presented the most optimized structure with a surface composed of many regular layered triangles. The specific capacitance of Er(1.5 at.%)/α-MnO2 electrodes reached 224.3 F g−1 at a current density of 0.25 A g−1 with a capacity retention ratio of 93.7% after 2000 cycles at a current density of 1.0 A g−1. The values were higher than those of α-MnO2 synthesized under the same conditions. Overall, these findings look promising for future applications of rare elements in modified MnO2.