P2-type Na2/3Ni1/3Mn2/3O2as a cathode materialwith high-rate and long-life for sodium ionstorage

Layered P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 was successfully synthesized through a facile sol-gel method and subsequent heat treatment. Resulting from different phase transformation and sodium ion diffusion rates, its electrochemical performance is highly related to the cut-off voltage and the electrolyte used. When the cut-off voltage is set up to 4.5 V or lowered to 1.5 V, capacity fade happens due to the occurrence of P2-O2 transformation and electrolyte decomposition or the redox reaction of the Mn 4+ /Mn 3+ ionic pair and P2-P2′ transformation. The electrode maintained 89.0 mA h g -1 with good cycling stability and excellent structural preservation between 4.0 and 2.0 V. The capacity retention is 71.2% even after 1200 cycles at 10C. It can be expected that P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 is very promising as a cathode material for sodium ion batteries

Electrochemical features of the interaction between (R)-/(S)-methyl-2- (5-fluorouracil-1-acetamide)-3-phenylpropionate and DNAs

398-403Cyclic voltammetry was exploited to understand the interaction between chiral methyl-2-(5- fluorouracil-1-acetamide)-3-phenylpropionate molecules (denoted as (R)- or (S)-5FUPPM) and double-stranded (ds) or G-quadruplex (G4) DNAs. Using Fe(CN)63- as the redox mark, experiments illustrate that the anodic peak of Fe(CN)63- oxidation decreases as the concentration of 5FUPPM in the solution is increased. Calculation with the Langmuir equation yields the binding equilibrium constant of 9.1 × 103 for the dsDNA and (S)-5FUPPM and of 3.3 × 103 for dsDNA and (R)-5FUPPM, suggesting that (S)-5FUPPM has more favorable interaction with dsDNA. On the other hand, the calculated binding constant between G4-DNA and (S)-5FUPPM is 1.6 × 104, as opposed to 3.2 × 104 between G4-DNA and (R)-5FUPPM. The results suggest that the binding selectivity of (R)-5FUPPM with DNAs, defined with (KG4-DNA/KdsDNA), is about 5 times larger than that of (S)-5FUPPM and DNAs, which is consistent with their inhibition rate on tumor cell. The information achieved here suggests that electrochemical characterization can provide useful information for the screening of new drug candidates

Rapid and controllable synthesis of nanocrystallized nickel-cobalt boride electrode materials via a mircoimpinging stream reaction for high performance supercapacitors

Nickel-cobalt borides (denoted as NCBs) have been considered as a promising candidate for aqueous supercapacitors due to their high capacitive performances. However, most reported NCBs are amorphous that results in slow electron transfer and even structure collapse during cycling. In this work, a nanocrystallized NCBs-based supercapacitor is successfully designed via a facile and practical microimpinging stream reactor (MISR) technique, composed of a nanocrystallized NCB core to facilitate the charge transfer, and a tightly contacted Ni-Co borates/metaborates (NCBi) shell which is helpful for OH^- adsorption. These merits endow NCB@NCBi a large specific capacity of 966 C g^-1 (capacitance of 2415 F g^-1) at 1 A g^-1 and good rate capability (633.2 C g^-1 at 30 A g^-1), as well as a very high energy density of 74.3 Wh kg^-1 in an asymmetric supercapacitor device. More interestingly, it is found that a gradual in situ conversion of core NCBs to nanocrystallized Ni-Co (oxy)-hydroxides inwardly takes place during the cycles, which continuously offers large specific capacity due to more electron transfer in the redox reaction processes. Meanwhile, the electron deficient state of boron in metal-borates shells can make it easier to accept electrons and thus promote ionic conduction

The Cathode Choice for Commercialization of Sodium-Ion Batteries: Layered Transition Metal Oxides versus Prussian Blue Analogs

2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim With the unprecedentedly increasing demand for renewable and clean energy sources, the sodium-ion battery (SIB) is emerging as an alternative or complementary energy storage candidate to the present commercial lithium-ion battery due to the abundance and low cost of sodium resources. Layered transition metal oxides and Prussian blue analogs are reviewed in terms of their commercial potential as cathode materials for SIBs. The recent progress in research on their half cells and full cells for the ultimate application in SIBs are summarized. In addition, their electrochemical performance, suitability for scaling up, cost, and environmental concerns are compared in detail with a brief outlook on future prospects. It is anticipated that this review will inspire further development of layered transition metal oxides and Prussian blue analogs for SIBs, especially for their emerging commercialization

Improving Mechanical, Electrical and Thermal Properties of Fluororubber by Constructing Interconnected Carbon Nanotube Networks with Chemical Bonds and F–H Polar Interactions

To improve the properties of fluororubber (FKM), aminated carbon nanotubes (CNTs-NH2) and acidified carbon nanotubes (CNTs-COOH) were introduced to modulate the interfacial interactions in FKM composites. The effects of chemical binding and F–H polar interactions between CNTs-NH2, CNTs-COOH, and FKM on the mechanical, electrical, thermal, and wear properties of the FKM composites were systematically investigated. Compared to the pristine FKM, the tensile strength, modulus at 100% strain, hardness, thermal conductivity, carbon residue rate, and electrical conductivity of CNTs-NH2/CNTs-COOH/FKM were increased by 112.2%, 587.5%, 44.2%, 37.0%, 293.5%, and nine orders of magnitude, respectively. In addition, the wear volume of CNTs-NH2/CNTs-COOH/FKM was reduced by 29.9%. This method provides a new and effective way to develop and design high-performance fluororubber composites

One-pot synthesis of dumbbell shaped PbS–Te hybrids with promising photothermal properties

The development of multi-component photothermal agents has attracted increasing attention due to their potential applications in energy conversion, medical treatments, etc. Herein, a dumbbell shaped PbS–Te heterostructure was prepared via a one-pot microwave-assisted decomposition of lead dimethyl dithiocarbamate and tellurium diethyl dithiocarbamate. The as-obtained PbS–Te hybrids exhibit excellent photothermal stability and strong optical absorption over a broad wavelength range spanning from ultraviolet to near-infrared, where the photothermal conversion efficiency could reach as high as 12.1%. Such promising photothermal performance demonstrates the advantages of one-pot synthesis that results in more intimate contacts among individual components.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Electrochemical Study of Polymorphic MnO2 in Rechargeable Aqueous Zinc Batteries

Manganese dioxide is regarded as a promising energy functional material due to its open tunnel structure with enormous applications in energy storage and catalysis. In this paper, α-MnO2 with a 2 × 2 tunnel structure and β-MnO2 with a 1 × 1 tunnel structure were hydrothermally synthesized, which possess characteristic tunnel structures formed by the interconnected unit structure of [MnO6] octahedrons. With regards to their different tunnel dimensions, the specific mechanism of ion intercalation in these two phases and the effect on their performance as aqueous Zn-MnO2 battery cathodes are explored and compared. Comprehensive analyses illustrate that both α-MnO2 and β-MnO2 provide decent capacity in the aqueous battery system, but their intrinsic stability is poor due to the structural instability upon cycling. At the same time, experiments show that α-MnO2 has a better rate performance than β-MnO2 under larger currents, thus implying that the former has a broader application in this aqueous battery system

Electrochemical Study of Polymorphic MnO₂ in Rechargeable Aqueous Zinc Batteries

Manganese dioxide is regarded as a promising energy functional material due to its open tunnel structure with enormous applications in energy storage and catalysis. In this paper, α-MnO2 with a 2 × 2 tunnel structure and β-MnO2 with a 1 × 1 tunnel structure were hydrothermally synthesized, which possess characteristic tunnel structures formed by the interconnected unit structure of [MnO6] octahedrons. With regards to their different tunnel dimensions, the specific mechanism of ion intercalation in these two phases and the effect on their performance as aqueous Zn-MnO2 battery cathodes are explored and compared. Comprehensive analyses illustrate that both α-MnO2 and β-MnO2 provide decent capacity in the aqueous battery system, but their intrinsic stability is poor due to the structural instability upon cycling. At the same time, experiments show that α-MnO2 has a better rate performance than β-MnO2 under larger currents, thus implying that the former has a broader application in this aqueous battery system