The rational design and fabrication of promising electrodes with prominent energy storage property and conversion performance is crucial for supercapacitors and electrocatalysis. Herein, potato chiplike cobalt nickel-layered double hydroxide@polypyrrole− cotton pad (CoNi-LDH@PCPs) composite was synthesized by in situ polymerization, which was coupled with facile solution reaction and ion-exchange etching process. An interesting potato chip-like structure can effectively expedite the kinetics of the electrode reactions, while the three-dimensional PCPs texture affords efficient pathways for charge transport, and the voids between adjacent fibers are thoroughly accessible for electrolytes and bubble evolution. When evaluated as a positive electrode for wearable supercapattery, the hierarchical CoNi-LDH@PCPs electrode displayed high specific capacity and excellent flexibility. As an oxygen evolution reaction catalyst, this PCPbased electrode also reveals the lowest overpotential of 350 mV at 10 mA cm −2 and a Tafel slope of ∼58 mV dec −1 . In addition, density functional theory calculations suggest that the synthesis strategy for controllable tuning of hollow CoNi-LDH arrays reported here represents a critical step toward high-performance electrodes for energy storage and electrochemical catalysis.
Hierarchical, mesoporous CuCo 2 O 4 nanograss has been synthesized on copper foam using a simple and cost-effective hydrothermal approach followed by a post-annealing treatment. The electrodes made from the novel nanoarchitecture exhibit multi-functional electrochemical performance. They deliver an excellent specific capacitance of 796 F g -1 at a current density of 2 A g -1 in a 2 M KOH aqueous solution and a long-term cyclic stability of 94.7% capacitance retention after 5000 cycles.When applied to electro-catalytic oxidation of methanol, the current density of the CuCo 2 O 4 /Cu foam electrode in 1 M KOH mixed with 0.5 M methanol is maintained up to 27.6 A g -1 . The superior electrochemical performances are mainly due to the unique one dimensional porous acicular architecture with very large surface area and 2 porosity grown on highly conductive Cu substrate, offering faster ion/electron transfer, an improved reactivity and an enhanced structural stability. The fabrication strategy presented here is simple, cost-effective and scalable, which can open new avenues for large-scale applications of the novel materials in energy storage.Fig. 5 (a, b) Low-magnification and high-magnification TEM images of an acicular CuCo 2 O 4 nanograss leaf; (c) corresponding SAED pattern; and (d) energy-dispersive X-ray spectrum of the elements Co, Cu and O.
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