An oxidation-resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge-like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single-layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m 2 g −1 ). Moreover, the graphene-based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a suffi cient capacitance (125 F g −1 ), wide potential window (4 V), and good rate capability as an electrode material for electric double-layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg −1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge-like elastic property enables an advanced force-induced adsorption control.

Cobalt oxide (Co3O4) and copper-doped cobalt oxide (CuxCo(3-x)O4) films have been prepared onto titanium support by the thermal decomposition method. The electrodes have been characterized by different techniques such as cyclic voltammetry, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The effect on the electrochemical and crystallographic properties and surface morphology of the amount of copper in the oxide layer has been analyzed. The XPS spectra correspond to a characteristic monophasic Cu-Co spinel oxides when x is below 1. However, when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuO phase segregates at the surface. The analysis of the surface cation distribution indicates that Cu(II) has preference for octahedral sites.

The possibility to store energy efficiently and sustainably at little cost is crucial to prevent climate change and exhaustion of natural resources. In this communication we demonstrate that interconnected and porous carbon fibers easily obtained from lignin exhibit ultrafast charge-discharge and excellent energy density and cyclability performance, to be used as binderless and flexible electrodes in supercapacitors.Electrochemical capacitors, usually referred to as supercapacitors, are electrochemical devices for electrical energy storage and harvesting applications that can complement or replace batteries when high power delivery or uptake and/or long cycling stability are required. Additionally, these devices improve efficiencies in supply systems (such as internal combustion engines, renewable energy systems, batteries and fuel cells) by storing energy when in excess or not needed. Thus, they are considered as one of the most powerful technologies that will provide a more efficient and sustainable utilization of energy on a short-term and real scenario of increasing energy costs and threatening climate change. 1 In spite of such relevance, the widespread utilization of supercapacitors has not been achieved due to a high cost to performance ratio. Among different electrode candidates, the last decade has witnessed a very intense research in the capacitance and storage performance of different nanostructured carbons, like graphene, CNTs, fullerenes, CNFs, onions, templated carbons, etc. 1 Nevertheless, apart from the significant progress on fundamental aspects, the complex and expensive manufacture as well as the complicated handling and electrode processing of these carbon materials make uncertain their feasible application. Accordingly, while novel electrode materials and chemistries are being developed to improve the storage performance, further research on simpler and cheaper manufacture and processing is demanded. Activated carbons (AC) derived from biomass and polymers have been identified as the currently most viable materials for supercapacitors, from both economic and sustainability points of view. 1a To attain the specifications for widespread commercialization, various issues need to be solved, being the most important to produce AC with a high accessible surface area and a sufficiently high electrical conductivity. On the one hand, biomass and natural polymers show a heterogeneous structure and contain impurities that complicate their processing to produce adequate conductive carbon electrodes. On the other hand, the derived ACs are conventionally obtained as powder or granular materials. Both the particle-like morphology and porosity strongly increase their inter-and intra-particle electrical resistances, 1e respectively, what makes necessary their processing into electrode pastes (by using auxiliary binders and conductivity promoters). This generates many electric point contacts that decrease their mechanical and chemical stability. 2 Hence the development of binderless porous carbons by a dire...