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A novel core–shell structured Co 11 (HPO 3 ) 8 (OH) 6 –Co 3 O 4 hybrid material was synthesized in a hydrothermal condition from the microporous Co 11 (HPO 3 ) 8 (OH) 6 microrod precursor. Due to the unique nano/microstructures, the assembled asymmetric all-solid-state supercapacitor (Co 11 (HPO 3 ) 8 (OH) 6 –Co 3 O 4 and graphene) showed a high gravimetric specific capacitance of 1.84 F cm −3 at 0.5 mA cm −2 and an excellent cycling stability with only 1.3% ca decay after 3000 cycling. The device delivered a maximum power density of 105 mW cm −3 at a current density of 1.5 mA cm −2 and possessed a maximum volumetric energy density of 0.48 mW h cm −3 at a current density of 0.5 mA cm −2 . The device also exhibited excellent flexibility. [ABSTRACT FROM AUTHOR]

1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures assembled by ultrathin nanoflakes are synthesized for the first time by a hydrothermal method. We present a self-reacting template method to synthesize 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures using Ni(SO 4 ) 0.3 (OH) 1.4 nanobelts. A high-performance flexible asymmetric solid-state supercapacitor can be successfully fabricated based on the 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures and graphene nanosheets. Interestingly, the as-assembled 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures//Graphene nanosheets asymmetric solid-state supercapacitor can achieve a maximum energy density of 0.496 mWh cm −3 , which is higher than most of reported solid state supercapacitors. Additionally, the device shows high cycle stability for 10,000 cycles. These features make the 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures as one of the most promising candidates for high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a novel macro–microporous architecture is successfully constructed in a honeycomb-like structure by directly using rape seed shell via impregation-activation route. This approach permits the high specific surface area (SSA) and a unique hierarchical porous structure which consists of interconnected macroporous skeleton and a significant microporosity. The unique honeycomb-like network combined with high specific surface area is favorable for charging the electric double-layer. The resulting carbon is highly suitable as electrodes of electric double layer capacitors, with remarkable values of capacitance of up to 225Fg−1 at a current density of 1Ag−1 in 2M KOH electrolyte. Therefore, the as-prepared carbon can be a potential candidate for supercapacitors. [Copyright &y& Elsevier]

Abstract: Two kinds of functionalized graphene sheets were produced by thermal exfoliation of graphite oxide. The first kind of functionalized graphene sheets was obtained by thermal exfoliation of graphite oxide at low temperature in air. The second kind was prepared by carbonization of the first kind of functionalized graphene sheets at higher temperature in N2. Scanning electron microscopy images show that both two kinds of samples possess nanoporous structures. The results of N2 adsorption–desorption analysis indicate that both of two kinds of samples have high BET surface areas. Moreover, the second kind of functionalized graphene sheets has a relatively higher BET surface area. The results of electrochemical tests is as follows: the specific capacitance values of the first kind of functionalized graphene sheets in aqueous KOH electrolyte are about 230Fg−1; the specific capacitance values of the second kind of functionalized graphene sheets with higher BET surface areas are only about 100Fg−1; however, compared with the first kind of functionalized graphene sheets, the second kind has a higher capacitance retention at large current density because of its good conductive behaviors; furthermore, in non-aqueous EC/DEC electrolyte, the specific capacitance values of the first kind sample and the second kind sample are about 73Fg−1 and 36Fg−1, respectively. [Copyright &y& Elsevier]