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

Abstract

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.