3D interconnected graphene aerogels (GAs) are prepared through one-step chemical reduction and rational assembly of graphene oxide (GO) sheets, so that the difficulties to uniformly disperse the individual graphene sheets in the polymer matrixes are avoided. Apart from ultralow density, high porosity, high electrical conductivity, and excellent compressibility, the resulting GAs possess a cellular architecture with a high degree of alignment when the graphene content is above a threshold, ∼0.5 wt %. The composites prepared by infiltrating GA with epoxy resin present excellent electrical conductivities, together with high mechanical properties and fracture toughness. The unusual anisotropic structure gives rise to ∼67% and ∼113% higher electrical conductivity and fracture toughness of the composites, respectively, in the alignment direction than that transverse to it.

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Nanocomposites consisting of ultrafine, cobalt carbonate nanoneedles and 3D porous graphene aerogel (CoCO3/GA) are in situ synthesized based on a one-step hydrothermal route followed by freeze-drying. A further heat treatment produces cobalt oxide nanoparticles embedded in the conductive GA matrix (Co3O4/GA). Both the composite anodes deliver excellent specific capacities depending on current density employed: the CoCO3/GA anode outperforms the Co3O4/GA anode at low current densities, and vice versa at current densities higher than 500 mA g–1. Their electrochemical performances are considered among the best of similar composite anodes consisting of CoCO3 or Co3O4 active particles embedded in a graphene substrate. The stable multistep electrochemical reactions of the carbonate compound with a unique nanoneedle structure contribute to the excellent cyclic stability of the CoCO3/GA electrode, whereas the highly conductive networks along with low charge transfer resistance are responsible for the high rate performance of the Co3O4/GA electrode.

A facile electrospinning method with subsequent heat treatments is employed to prepare carbon nanofibers (CNFs) containing uniformly dispersed Co3O4 nanoparticles as electrodes for supercapacitors. The Co3O4/CNF electrodes with ∼68 wt % active particles deliver a remarkable capacitance of 586 F g(-1) at a current density of 1 A g(-1). When the current density is increased to 50 A g(-1), ∼66% of the original capacitance is retained. The electrodes also present excellent cyclic stability of 74% capacity retention after 2000 cycles at 2 A g(-1). These superior electrochemical properties are attributed to the uniform dispersion of active particles in the CNF matrix, which functions as a conductive support. The onionlike graphitic layers formed around the Co3O4 nanoparticles not only improve the electrical conductivity of the electrode but also prevent the separation of the nanoparticles from the carbon matrix.

A low crystallinity SnO2/CNT composite anode delivers a superior electrochemical performance in Na-ion batteries through enhanced kinetics of conversion reactions with a faster ion diffusion rate.

This paper reports a facile route to synthesize porous carbon nanofibers containing cobalt and cobalt oxide nanoparticles (CoOx/PCNF) as anodes for Li-ion batteries.