RESUMO
Large-scale durable aqueous zinc ion batteries for stationary storage are realized by spray-coating conductive PEDOT(Poly(3,4-ethylenedioxythiophene)) wrapping MnO2/carbon microspheres hybrid cathode in this work. The porous carbon microspheres with multiple layers deriving from sucrose provide suitable accommodation for MnO2 active materials, exposing more redox active sites and enhancing the contact surface between electrolyte and active materials. As a result, MnO2/microspheres are adhered to the current collector by a conductive PEDOT coating without any binder. The ternary design retards the structural degradation during cycling and shortens the electron and ion transport path, rendering the full batteries high capacity and long cycle stability. The resulting batteries perform the capacity of 277, 227, 110, 85 and 50 mAh/g at 0.2, 0.5, 1, 2 and 5 A/g, respectively. After 3000 cycles the initial capacity retains 86%, and 80% after 5000 cycles. GITT indicates PEDOT wrapping MnO2/microspheres cathode enables better ion intercalating kinetics than conventional MnO2. The work could represent a novel and significant step forward in the studies on the large-scale application of zinc ion batteries.
RESUMO
Nickel-based hydroxides and their derivatives exhibit relatively low capacities and unsatisfactory durability as cathode materials for rechargeable alkaline batteries. In this work, a hybrid NiCo-B nanosheet cathode, integrating electrolyte ion-shuttling channels and electron-transferring networks into a metal-organic framework (MOF), was devised delicately. In the structure, the hybrid ion/electron dual pathways were constructed by NiCo-MOF frameworks and NiCo-B interpenetration networks. It revealed that nano-phase electron-transferring pathways in the MOF obviously boosted ion intercalation kinetics. The as-obtained hybrid NiCo-B nanosheets as cathode materials exhibited reversible capacity as high as 280 mA h g-1 at a current density of 1 A g-1 and excellent rate capability with a capacity retention of 78% from 1 to 10 A g-1. After 2000 charge/discharge cycles at 4 A g-1, the capacity still remained at 94% of the initial one. A full battery assembled with a hybrid NiCo-B cathode and a Fe2O3 anode showed a high capacity of 250 mA h g-1 and a considerable stability of 89% after 1000 cycles. Ragone plots indicated the highest energy density of 409 W h kg-1 and the lowest power density of 1.5 kW kg-1, outperforming other aqueous batteries. It revealed that a syngenetic structure of ion/electron hybrid dual pathways integrated into an MOF could be a potential strategy to optimize ion intercalation electrode materials for alkaline batteries.
RESUMO
The coupled photocatalyst of CdS/TiO2/float pearls was prepared by sol-gel-dipping method, and its structure characterization was carried out with SEM and XRD analysis. As a model reaction, the photocatalytic degradation of beta-cypermethrin (BEC) was investigated in CdS/TiO2/float pearls powder suspension irradiated by different light sources. The effects of influence factors on the photocatalytic activity were discussed for the prepared photocatalyst. The results showed that under the following conditions: amount of photocatalyst 3000 mg x L(-1), initial concentration of BEC 45 mg x L(-1), initial pH 6. 5, and air flow rate 200 mL x min(-1), the degradation rate of BEC reached 87.9% (125 W Hg lamp in 1 hour), 79.3% (5 W UV lamp in 1 hour) and 93.4% (solar light in 5 hours), respectively. The photocatalytic degradation of BEC was experimentally demonstrated to follow the Langmuir-Hinshelwood kinetic model, and the reaction rate constant (9.80 mg x (L x min)(-1)) and the adsorption constant (4.36 x 10(-3) L x mg(-1)) were determined, respectively.