关键词: 纳米结构, Mn掺杂, 腐蚀, 氧化, 超级电容器

Abstract:

With the merits of high theoretical specific capacitance and abundant reserves, copper oxides have become next-generation electrode materials for supercapacitors, but their applications are still limited to the poor electron conductivity and inferior cyclic stability. In this work, the sandwich-like Cu₃₀Mn₇₀/Cu/Cu₃₀Mn₇₀ foil was used as mother-alloy. A highly conductive and flexible nano-porous CuMn-core and multicomponent oxide-shell electrode with different Mn residues was prepared by the combination of dealloying and self-propagating oxidation. The effect of Mn residues on the morphology, structure and electrochemical properties of the electrode under different dealloying conditions was investigated. The experimental results showed that the residual amount of Mn would gradually decrease along with extension of corrosion time. The multicomponent oxides obtained under different corrosion conditions were composed of CuO, Cu₂O, Cu _x Mn_1-x O and CuMn₂O₄ phases. In three electrode system, the NP-TMO5 sample indicated the highest area capacitance of 1045.7mF/cm² at current density of 5mA/cm² and maintained 97.9% capacitance after 12000 cycles. The symmetric device composed by NP-TMO5 delivered high area capacitance and energy density of 419.83mF/cm² and 0.084mWh/cm² at current density of 3mA/cm², respectively. Even after 10000 cycles at a scanning rate of 100mV/s, the specific capacitance retention was still 97.9%. The excellent performance of the sample was attributed to the core-shell structure of the porous electrode and the synergistic effect between multi-component oxides, which can optimize the electronic structure and buffer the volume expansion, providing a theoretical basis for the design of highly loaded composite porous structures.

Key words: nanostructure, Mn doping, corrosion, oxidation, supercapacitors