We fabricated a robust electrocatalyst by chemically depositing an ultrathin layer of amorphous molybdenum sulfide on the internal surface of dealloyed nanoporous gold. The catalyst exhibits superior electrocatalysis toward hydrogen evolution reaction in both acidic and neutral media with 2-6 times improvement in catalytic activies compared to other molybdenum sulfide based materials.

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High energy density, durability, and flexibility of supercapacitors are required urgently for the next generation of wearable and portable electronic devices. Herein, a novel strategy is introduced to boost the energy density of flexible soild-state supercapacitors via rational design of hierarchically graphene nanocomposite (GNC) electrode material and employing an ionic liquid gel polymer electrolyte. The hierarchical graphene nanocomposite consisting of graphene and polyaniline-derived carbon is synthesized as an electrode material via a scalable process. The meso/microporous graphene nanocomposites exhibit a high specific capacitance of 176 F g −1 at 0.5 A g −1 in the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF 4 ) with a wide voltage window of 3.5 V, good rate capability of 80.7% in the range of 0.5-10 A g −1 and excellent stability over 10 000 cycles, which is attributed to the superior conductivity (7246 S m −1 ), and quite large specific surface area (2416 m 2 g −1 ) as well as hierarchical meso/micropores distribution of the electrode materials. Furthermore, flexible solid-state supercapacitor devices based on the GNC electrodes and gel polymer electrolyte film are assembled, which offer high specific capacitance of 180 F g −1 at 1 A g −1 , large energy density of 75 Wh Kg −1 , and remarkable flexible performance under consecutive bending conditions.

A binder-free self-grown oxy-hydroxide@nanoporous Ni-Mn hybrid electrode with high capacitance and cyclic stability is fabricated by electrochemical polarization of a dealloyed nanoporous Ni-Mn alloy. Combined with the low material costs, high electrochemical stability, and environmentally friendly nature, this novel electrode holds great promise for applications in high-capacity commercial supercapacitors.