Royal Society of Chemistry, Journal of Materials Chemistry A: materials for energy and sustainability, 19(3), p. 10519-10525
DOI: 10.1039/c5ta01071c
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Although the NiO nanostructures potentially hold outstanding electrochemical activity in theory, dual enhancements in both electrical conductivity and electrolyte transport are two challenging issues for designing high performance electrodes. In this work, the hierarchical porous Ni/NiO core-shells are synthesized. The interconnected Ni skeletons with favorable electrical conductivity are uniformly covered by the continuous NiO scarfskins that hold both high energy storage capacity and the efficient catalysis. Hierarchical porous Ni/NiO electrode exhibits superior pseudo-capacitive performance evidenced by areal capacitance up to 255 mF cm−2. Meanwhile, this conductive electrode also exhibits electrocatalytic activity for glucose oxidation with the sensitivity towards 4.49 mA mM-1 cm-2 and reliable detection limit towards 10 M. On the other hand, hierarchical porosities enhance the effective transport of electrolytes and ions within the interconnected porous channels, making the dramatic contributions to superior storage stability towards 4000 cycles and prompt amperometric response time towards 1.5 s. These concepts of hierarchical metal-metal oxide core-shell open an avenue to design high-performance materials for energy storage and electrochemical catalysis.