Hierarchical porous architecture on Ni foam created via an oxidization-reduction process and its application for supercapacitor

Three-dimensional (3D) porous metals, particularly those with a hierarchical porous architecture, are the desirable current collector for a wide variety of electrochemical devices. It is highly desirable to develop a facile process for fabrication of such metallic architectures. Here we propose a novel strategy, oxidization and reduction process, to in situ create micron-scale pores on the ligaments of the commercial Ni foam. Through this simple process, a hierarchical microporous Ni foam (HMNF) composed of large pore channels and micron-scale pores in skeleton is created. This process is simple and green, avoiding the use of sacrificial materials. Furthermore, nanocrystalline MnO 2 is coated on a HMNF to construct a supercapacitor electrode. The results indicate that the created micron porous architectures of the HMNF-MnO 2 electrode enhance not only the electrochemical performance but also the mechanical robustness, leading to a high capacitance and excellent cycling stability.