Hierarchical 3-dimensional CoMoO4 nanoflakes on a macroporous electrically conductive network with superior electrochemical performance

摘要

Nanoscale cobalt molybdate (CoMoO4) particles are fabricated hydrothermally on the surface and sidewall of three-dimensional nickel-coated silicon microchannel plates (also called macroporous electrically conductive network, MECN) as the active electrode in a miniature energy storage device. The relationships between the reaction time, morphology, formation mechanism of the CoMoO4 nanostructure, and electrochemical performance are studied. After an optimal hydrothermal synthesis time of 2.5 h, the CoMoO4 electrode has a capacity of 32.40 mA h g(-1) (492.48 mu A h cm(-2)) at constant current density of 1 A g(-1) and retention ratio of 85.98% after 5000 cycles. The large specific capacity and excellent rate capability can be attributed to the unique 3D ordered porous architecture which facilitates electron and ion transport, enlarges the liquid-solid interfacial area, and enhances the utilization efficiency of the active materials. Furthermore, the weight and size of the device are reduced. By using the CoMoO4/MECN electrode as the positive electrode and carbonickel foam (carbon/NF) as the negative electrode, the faradaic electrode was packaged by a CR2025 battery cell as the miniature hybrid device exhibits stable power characteristics (5000 cycle times with 71.82% retention). After charging each hybrid device for 10 s, three devices in series can power two 5 mm diameter light-emitting diodes (LED) efficiently.