Supercapacitors have attracted intense attention due to their great potential to meet the demand of both high energy density and power density in many advanced technologies. Various carbon-based nanocomposites are currently pursued as supercapacitor electrodes because of the synergistic effect between carbon (high power density) and pseudo-capacitive nanomaterials (high energy density). This feature article aims to review most recent progress on 3D (3D) carbon based nanostructures for advanced supercapacitor applications in view of their structural intertwinement which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The carbon nanostructures comprise of CNTs-based networks, graphenebased architectures, hierarchical porous carbon-based nanostructures and other even more complex carbon-based 3D configurations. Their advantages and disadvantages are compared and summarized based on the results published in the literature. In addition, we also discuss and view the ongoing trends in materials development for advanced supercapacitors. Broader contextSupercapacitors are one of the crucial devices for energy storage applications as they can provide higher power density than batteries and higher energy density than conventional dielectric capacitors. Many materials have been investigated as electrode materials for supercapacitors. Among them, carbon materials with various microtextures are considered as the main candidate for supercapacitors in terms of high surface area, interconnected pore structure, controlled pore size, high electrical conductivity and environmental friendliness. Nevertheless, pure carbon materials encounter difficulties in meeting the requirements of high energy storage devices even with the ne-tuned pore structures due to their energy storage mechanism which is a purely physical process. To further improve the energy density of supercapacitors without sacrice of power density, carbon-based composites combining electrical double layer capacitance and pseudocapacitance have been extensively explored, demonstrating enhanced capacitance as well as good cycling stability. In this review, recent progress on the 3D carbon based nanostructures encompassing the CNTs-based networks, graphene-based architectures, hierarchical porous carbon-based nanostructures and even more complex carbon-based 3D conguration for advanced supercapacitor applications is summarized, shedding light on their structural interconnectivities, which not only create hierarchical porous channels, but also lead to higher electrical conductivity and better structural mechanical stability. Their advantages and disadvantages are discussed, new trends of electrode materials for high-performance supercapacitors are also proposed.

We demonstrate a simple and scalable strategy for synthesizing hierarchical porous NiCo(2)O(4) nanowires which exhibit a high specific capacitance of 743 F g(-1) at 1 A g(-1) with excellent rate performance (78.6% capacity retention at 40 A g(-1)) and cycling stability (only 6.2% loss after 3000 cycles).

A novel strategy for the controlled synthesis of 2D MoS2/C hybrid nanosheets consisting of the alternative layer-by-layer interoverlapped single-layer MoS2 and mesoporous carbon (m-C) is demonstrated. Such special hybrid nanosheets with a maximized MoS2 /m-C interface contact show very good performance for lithium-ion batteries in terms of high reversible capacity, excellent rate capability, and outstanding cycling stability.

Searching the long-life MnO-based materials for lithium ion batteries (LIBs) is still a great challenge because of the issue related to the volumetric expansion of MnO nanoparticles (NPs) or nanowires (NWs) during lithiation. Herein, we demonstrate an unexpected result that a peapod-like MnO/C heterostructure with internal void space can be facilely prepared by annealing the MnO precursor (MnO-P) NW/polydopamine core/shell nanostructure in an inert gas, which is very different from the preparation of typical MnO/C core/shell NWs through annealing MnO NW/C precursor nanostructure. Such peapod-like MnO/C heterostructure with internal void space is highly particular for high-performance LIBs, which can address all the issues related to MnO dissolution, conversion, aggregation and volumetric expansion during the Li(+) insertion/extraction. They are highly stable anode material for LIBs with a very high reversible capacity (as high as 1119 mAh g(-1) at even 500 mA g(-1)) and fast charge and discharge capability (463 mAh g(-1) at 5000 mA g(-1)), which is much better than MnO NWs (38 mAh g(-1) at 5000 mA g(-1)) and MnO/C core/shell NWs (289 mAh g(-1) at 5000 mA g(-1)). Such nanopeapods also show excellent rate capability (charged to 91.6% in 10.6 min using the constant current mode). Most importantly, we found that MnO/C nanopeapods show no capacity fading even after 1000 cycles at a high current density of 2000 mA g(-1), and no morphology change. The present MnO/C nanopeapods are the most efficient MnO-based anode materials ever reported for LIBs.

Supercapacitors have attracted huge attention in recent years as they have the potential to satisfy the demand of both huge energy and power density in many advanced technologies. However, poor conductivity and cycling stability remains to be the major challenge for its widespread application. Various strategies have been developed for meeting the ever-increasing energy and power demands in supercapacitors. This Research News article aims to review recent progress in the development of mesoporous carbon incorporated metal oxide nanomaterials, especially metal oxide nanoparticles confined in ordered mesoporous carbon and 1D metal oxides coated with a layer of mesoporous carbon for high-performance supercapacitor applications. In addition, a recent trend in supercapacitor development - hierarchical porous graphitic carbons (HPGC) combining macroporous cores, mesoporous walls, and micropores as an excellent support for metal oxides - is also discussed.

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A flexible and robust electrode is demonstrated by assembling the 3D ordered macroporous MoS @C nanostructure on carbon cloth with ultrasmall few-layered MoS nanosheets homogenously embedded into the interconnected carbon wall. Such unique nanostructures are favorable for enhancing lithium storage capacity, directly applied as a flexible electrode, demonstrating a very high electrochemical performance and superior cycling stability for lithium-ion batteries.

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