No abstract

A soft-hard template-assisted method toward the unconventional free-standing ordered mesoporous carbon sheets (OMCSs) with uniform hexagonal morphology is developed by applying MgAl-layered double hydroxide (MgAl-LDH) as the hard template, triblock copolymer F127 as the soft template, and phenolic resols as the carbon sources. It is found that the surface of MgAl-LDH can induce the morphology variation of resol-F127 monomicelles, leading to the formation of vertically or horizontally aligned mesopore arrays in the OMCSs, which can in turn determine their electrochemical energy storage behaviors in supercapacitors with different configurations. In an all-solid-state supercapacitor with two face-to-face electrodes, an OMCS with vertical mesopores manifests the best performance among the samples. By contrast, in a micro-supercapacitor with in-plane film-like electrodes, an OMCS with horizontal mesopores delivers higher energy/power densities than the other OMCSs, which are also comparable to the state-of-the-art supercapacitors based on ordered mesoporous carbons. The achievement of uniform carbon sheets with orientation-adjustable mesopore arrays can help elucidate their electrochemical storage mechanism and allow the optimization of the performances according to the device configuration, thus providing a powerful tool for the manipulation of energy storage devices on the nanoscale.

The ultrastable metal electrodes that can withstand the mechanical deformations of the soft substrates are always essential for the development of flexible supercapacitors. However, the metal electrode physically deposited on the flexible substrate is rigid and delaminated, and the contact interface is easily degraded under the mechanical cycling. The highly flexible and conductive composites with the intermixed metal−polymer structure as electrodes are key to solving the contact problem. In this work, a universal and facile method for flexible micro-supercapacitors (MSCs) with combination of nickel electroless plating (EN) and reduced graphene oxide (rGO) electrodeposition was presented. The so-called surface exchange and ion exchange (SMIE) technique has been employed to prepare the seed layer, and the electroless plating was conducted to deposit the Ni−P layer. The rGO-coated (GC) layer was then electrodeposited onto the Ni−P layer to form an EN/GC composite structure. EN/GC electrodes with symmetric interdigitated electrodes were fabricated at room temperature via an all-solution method. Due to the novel intermixed Nipolyimide interfacial structure, the highly flexible and mechanically stable EN/GC layer was formed. The introduction of GC enables the composite structure to be highly electrochemically stable. The result indicated that EN/GC electrodes exhibit superior charging and discharging performance without obvious capacitance degradation. The flexible micro-supercapacitors with EN/GC electrodes were also demonstrated and can work after 10 000 cycles of bending tests. The developed technology is compatible with the batch fabrication process and can be used to fabricate MSCs with high electrochemical stability.