Low-temperature synthesis of Mn3O4 hollow-tetrakaidecahedrons and their application in electrochemical capacitors

Mn3O4 hollow-tetrakaidecahedron micro/nano structures are synthesized basing on a structure-shrinkage-assisted Kirkendall effect under the hydrothermal condition. The Mn powders are transformed into Mn(OH)(2) micro tetrakaidecahedron and substantially oxidized to Mn3O4 during the filtration under the flow of oxygen. The Kirkendall effect was proposed to have important responsibility on the formation of voids. Due to the structural shrinkage while transformation, the diffusion of substances from core to shell was found to be accelerated and thus larger holes formed. Electrochemical behavior of such hollow structure electrode was 148 F g(-1). Mn2O3 and Mn5O8 micro hollow tetrakaidecahedron could also be obtained by annealing the corresponding Mn3O4 tetrakaidecahedrons in the air at different temperature.