Large scale energy storage system with low cost, high power, and long cycle life is crucial for addressing the energy problem when connected with renewable energy production. To realize grid-scale applications of the energy storage devices, there remain several key issues including the development of low-cost, high-performance materials that are environmentally friendly and compatible with low-temperature and large-scale processing. In this report, we demonstrate that solution-exfoliated graphene nanosheets (∼5 nm thickness) can be conformably coated from solution on three-dimensional, porous textiles support structures for high loading of active electrode materials and to facilitate the access of electrolytes to those materials. With further controlled electrodeposition of pseudocapacitive MnO(2) nanomaterials, the hybrid graphene/MnO(2)-based textile yields high-capacitance performance with specific capacitance up to 315 F/g achieved. Moreover, we have successfully fabricated asymmetric electrochemical capacitors with graphene/MnO(2)-textile as the positive electrode and single-walled carbon nanotubes (SWNTs)-textile as the negative electrode in an aqueous Na(2)SO(4) electrolyte solution. These devices exhibit promising characteristics with a maximum power density of 110 kW/kg, an energy density of 12.5 Wh/kg, and excellent cycling performance of ∼95% capacitance retention over 5000 cycles. Such low-cost, high-performance energy textiles based on solution-processed graphene/MnO(2) hierarchical nanostructures offer great promise in large-scale energy storage device applications.

No abstract

Covalent organic polymers (COPs) provide an interesting platform for constructing the low-cost and highly efficient multifunctional electrocatalysts in view of their tailorable structures and properties. Herein, Co-phthalocyanine-based COPs (CoPc-COPs) are constructed using cobalt tetraaminophthalocyanine (CoPc­(NH2)4) as the organic building unit and phosphonitrilic chloride trimer (Cl6N3P3) as the linker group, which serve as the self-carrier enriched with Co, P, N, and C to derive Co2P nanoparticles anchored on the N, P codoped graphene after carbonization treatment. Benefiting from the unique construction and the metallic property confirmed by density functional theory (DFT) calculations, the Co2P/NPG displays high-efficient trifunctional electrocatalytic performance toward oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER), including excellent oxygen electrocatalytic activity (overpotential of 0.32 V at 10 mA cm–2 for OER, half-wave potential of 0.81 V for ORR) and outstanding stability (98% over 12 h for OER, 89% over 17 h for ORR). Impressively, rechargeable Zn-air batteries (ZABs) that employed Co2P/NPG as the cathode electro-catalyst display a peak power of up to 103.5 mW cm–2 along with a good cycle stability after 55 h. Moreover, the constructed ZABs can be used to power the overall water splitting. Therefore, function-oriented design of metallophthalocyanine-based COPs provides new ways to strategically construct multifunctional electrocatalysts for the wider integrated green energy system.

We report a new approach to construct covalent porphyrinic cages with different spacer lengths, in which the cage compounds have been conveniently synthesized in quantitative yields, via DABCO-templated imine condensation reactions.

No abstract