The application of conventional metal–organic frameworks (MOFs) as electrode materials in supercapacitors is largely hindered by their conventionally poor electrical conductivity. This study reports the fabrication of conductive MOF nanowire arrays (NWAs) and the application of them as the sole electrode material for solid‐state supercapacitors. By taking advantage of the nanostructure and making full use of the high porosity and excellent conductivity, the MOF NWAs in solid‐state supercapacitor show the highest areal capacitance and best rate performance of all reported MOF materials for supercapacitors, which is even comparable to most carbon materials.
A flexible nanoporous carbon-fiber film for wearable electronics is prepared by a facile and scalable method through pyrolysis of electrospun polyimide. It exhibits excellent bifunctional electrocatalytic activities for oxygen reduction and oxygen evolution. Flexible rechargeable zinc-air batteries based on the carbon-fiber film show high round-trip efficiency and mechanical stability.
Identification of
catalytic sites for oxygen reduction reaction
(ORR) and oxygen evolution reaction (OER) in carbon materials remains
a great challenge. Here, we construct a pyridinic-N-dominated doped
graphene with abundant vacancy defects. The optimized sample with
an ultrahigh pore volume (3.43 cm3 g–1) exhibits unprecedented ORR activity with a half-wave potential
of 0.85 V in alkaline. For the first time, density functional theory
results indicate that the quadri-pyridinic N-doped carbon site synergized
with a vacancy defect is the active site, which presents the lowest
overpotential of 0.28 V for ORR and 0.28 V for OER. The primary Zn–air
batteries display a maximum power density of 115.2 mW cm–2 and an energy density as high as 872.3 Wh kg–1. The rechargeable Zn–air batteries illustrate a low discharge–charge
overpotential and high stability (>78 h). This work provides new
insight
into the correlation between the N configuration synergized with a
vacancy defect in electrocatalysis.
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