Potassium ion storage technology as a promising substitute for the well‐developed lithium ion storage technology is still at the infancy stage of development, and exploring suitable electrode ...materials is critical for its practical application. Here, the great feasibility of disordered, large interlayer spacing, and oxygen‐rich carbon nanosheets (CNSs) prepared by chemical vapor deposition for potassium ion storage applications is demonstrated. As an anode material, the CNSs exhibit outstanding rate capability as well as excellent cyclic stability. Taking advantage of this, a potassium ion hybrid capacitor (PIHC) is constructed by employing such CNSs as the battery‐type anode and activated carbon as the capacitor‐type cathode. The resulting device displays a high energy density of 149 Wh kg−1, an ultrahigh power output of 21 kW kg−1, as well as a long cycling life (80% capacity retention after 5000 cycles), which are all close to the state‐of‐the‐art values for PIHCs. This work promotes the development of high‐performance anode material for potassium ion storage devices, and the designed PIHC pushes the energy density and power density to a higher level.
Employing Na2CO3 as template, disordered, large interlayer spacing, and oxygen‐rich carbon nanosheets (CNSs) are prepared by chemical vapor deposition. Such CNS anodes exhibit superior performance for potassium ion storage, and thus the resulting potassium ion hybrid capacitor displays a good overall performance, high energy density, high power density as well as long cycling life.
Carbon sheets with 3D architectures, large graphitic interlayer spacing, and high electrical conductivity are highly expected to be an ideal anode material for sodium‐ion hybrid capacitors (SIHCs). ...Pursuing a simple synthesis methodology and advancing it from the laboratory to industry is of great importance. In this study, a new approach is presented to prepare 3D framework carbon (3DFC) with the above integrated advantages by a direct calcination of sodium citrate without aid of any additional carbon source, template, or catalyst. The first‐principle calculations verify that the large interlayer spacing and the curvature structure of 3DFC facilitate the sodium ion insertion/extraction. As a consequence, the optimal 3DFC sample exhibits high reversible capacity as well as excellent rate and cycling performance. On this basis, a dual‐carbon SIHC is fabricated by employing 3DFC as battery‐type anode and 3DFC‐derived nanoporous carbon as capacitor‐type cathode. It is able to deliver high energy‐ and power‐density feature as well as outstanding long‐term cycling stability in the potential range of 0–4.0 V. This study may open an avenue for developing high‐performance carbon electrode materials and pushes the practical applications of SIHCs a decisive step forward.
A simple, low‐cost, and large‐scale preparation of 3D framework carbon (3DFC) with large interlayer spacing, curved interface, and high conductivity is proposed. The as‐prepared 3DFC anode exhibits excellent sodium storage performance. On this basis, an advanced dual‐carbon sodium‐ion hybrid capacitor is fabricated by employing such 3DFC as battery‐type anode and 3DFC‐derived nanoporous carbon as capacitor‐type cathode.
Supercapacitors based on activated carbon electrodes and ionic liquids as electrolytes are capable of storing charge through the electrosorption of ions on porous carbons and represent important ...energy storage devices with high power delivery/uptake. Various computational and instrumental methods have been developed to understand the ion storage behavior, however, techniques that can probe various cations and anions of ionic liquids separately remain lacking. Here, we report an approach to monitoring cations and anions independently by using silica nanoparticle-grafted ionic liquids, in which ions attaching to silica nanoparticle cannot access activated carbon pores upon charging, whereas free counter-ions can. Aided by this strategy, conventional electrochemical characterizations allow the direct measurement of the respective capacitance contributions and acting potential windows of different ions. Moreover, coupled with electrochemical quartz crystal microbalance, this method can provide unprecedented insight into the underlying electrochemistry.
Oxytetracycline (OTC) is a kind of widely used veterinary drugs. The residue of OTC in the environment is potentially harmful. In the present work, the interaction between OTC and bovine hemoglobin ...(BHb) was investigated by fluorescence, synchronous fluorescence, UV–vis absorption, circular dichroism and molecular modeling techniques under physiological conditions. The experimental results showed that OTC can bind with BHb to form complex. The binding process is a spontaneous molecular interaction procedure, in which van der Waals and hydrogen bonds interaction play a major role. The number of binding sites were calculated to be 1.12 (296
K), 1.07 (301
K) and 0.95 (308
K), and the binding constants were of
K
296
K
=
9.43
×
10
4
L
mol
−1,
K
301
K
=
4.56
×
10
4
L
mol
−1 and
K
308
K
=
1.12
×
10
4
L
mol
−1 at three different temperatures. Based on the Förster theory of nonradiative energy transfer, the binding distance between OTC and the inner tryptophan residues of BHb was determined to be 2.37
nm. The results of UV–vis absorption, synchronous fluorescence and CD spectra indicated that OTC can lead to conformational and some microenvironmental changes of BHb, which may affect physiological functions of hemoglobin. The synchronous fluorescence experiment revealed that OTC binds into hemoglobin central cavity, which was verified by molecular modeling study. The work is helpful for clarifying the molecular toxic mechanism of OTC in vivo.
Functional oligosaccharides, known as prebiotics, and ordinary dietary fiber have important roles in modulating the structure of intestinal microbiota. To investigate their effects on the intestinal ...microecosystem, three kinds of diets containing different prebiotics were used to feed mice for 3 weeks, as follows: GI (galacto-oligosaccharides and inulin), PF (polydextrose and insoluble dietary fiber from bran), and a GI/PF mixture (GI and PF, 1:1), 16S rRNA gene sequencing and metabolic analysis of mice feces were then conducted. Compared to the control group, the different prebiotics diets had varying effects on the structure and diversity of intestinal microbiota. GI and PF supplementation led to significant changes in intestinal microbiota, including an increase of
and a decrease of
in the GI-fed, but those changes were opposite in PF fed group. Intriguing, in the GI/PF mixture-fed group, intestinal microbiota had the similar structure as the control groups, and flora diversity was upregulated. Fecal metabolic profiling showed that the diversity of intestinal microbiota was helpful in maintaining the stability of fecal metabolites. Our results showed that a single type of oligosaccharides or dietary fiber caused the reduction of bacteria species, and selectively promoted the growth of
or
bacteria, resulting in an increase in diamine oxidase (DAO) and/or trimethylamine N-oxide (TMAO) values which was detrimental to health. However, the flora diversity was improved and the DAO values was significantly decreased when the addition of nutritionally balanced GI/PF mixture. Thus, we suggested that maintaining microbiota diversity and the abundance of dominant bacteria in the intestine is extremely important for the health, and that the addition of a combination of oligosaccharides and dietary fiber helps maintain the health of the intestinal microecosystem.
Graphene nanoscrolls (GNSs) are receiving intense interest because they are expected to possess some peculiar properties quite distinct from both graphene and carbon nanotubes. Research on GNS, ...however, has been hindered by limitations of the available preparation methods. Here we demonstrate a novel strategy for the large-scale preparation of GNSs from graphene oxide (GO) sheets by cold quenching, freeze-drying and subsequent thermal reduction. When a plastic box with a heated GO aqueous suspension is immersed in liquid nitrogen, GO sheets are able to roll up and most GNSs have diameters ranging from 200 to 600nm. More interestingly, these GNSs connect each other to form a 3D network. The structural conversion is closely correlated with the initial temperature of GO suspension, the size of GO sheets and the immersion way. The liquid nitrogen cold quenching is a simple and controllable method for large-scale preparation of GNSs. The liquid nitrogen cold quenching is a simple and controllable method for large-scale preparation of GNSs.
Via an in situ prepared gel polymer electrolyte, we realized a flexible and safe Li metal capacitor with high capacitance (210 F/g at 0.1 A/g within 1.5–4.3 V vs. Li/Li+), high energy density (474 ...Wh/kg) and high power density (29 kW/kg).
Display omitted
The rapid development of next-generation flexible electronics stimulates the growing demand for flexible and wearable power sources with high energy density. Li metal capacitor (LMC), combining with a Li metal anode and an activated carbon cathode, exhibits extremely high energy density and high power density due to the unique energy storage mechanism, thus showing great potential for powering wearable electronic devices. Herein, a flexible LMC based on an in situ prepared PETEA-based gel polymer electrolyte (GPE) was reported for the first time. Owing to the high ionic conductivity of PETEA-based GPE (5.75 × 10−3 S/cm at 20 °C), the assembled flexible LMC delivers a high capacitance of 210 F/g at 0.1 A/g within the voltage range from 1.5 V to 4.3 V vs. Li/Li+, a high energy density of 474 Wh/kg at 0.1 A/g and a high power density of 29 kW/kg at 10 A/g. More importantly, PETEA-based GPE endows the LMC with excellent flexibility and safety, which could work normally under abuse tests, such as bending, nail penetration and cutting. The in situ prepared PETEA-based GPE simplifies the fabrication process, avoids the risk of leakage and inhibits the growth of Li dendrite, making LMC a promising flexible energy storage device for the flexible electronic field.
Lung adenocarcinoma (LUAD) is one of the most lethal malignancies and is currently lacking in effective biomarkers to assist in diagnosis and therapy. The aim of this study is to investigate hub ...genes and develop a risk signature for predicting prognosis of LUAD patients.
RNA-sequencing data and relevant clinical data were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was performed to identify hub genes associated with mRNA expression-based stemness indices (mRNAsi) in TCGA. We utilized LASSO Cox regression to assemble our predictive model. To validate our predictive model, me applied it to an external cohort.
mRNAsi index was significantly associated with the tissue type of LUAD, and high mRNAsi scores may have a protective influence on survival outcomes seen in LUAD patients. WGCNA indicated that the turquoise module was significantly correlated with the mRNAsi. We identified a 9-gene signature (CENPW, MCM2, STIL, RACGAP1, ASPM, KIF14, ANLN, CDCA8, and PLK1) from the turquoise module that could effectively identify a high-risk subset of these patients. Using the Kaplan-Meier survival curve, as well as the time-dependent receiver operating characteristic (tdROC) analysis, we determined that this gene signature had a strong predictive ability (AUC = 0.716). By combining the 9-gene signature with clinicopathological features, we were able to design a predictive nomogram. Finally, we additionally validated the 9-gene signature using two external cohorts from GEO and the model proved to be of high value.
Our study shows that the 9-gene mRNAsi-related signature can predict the prognosis of LUAD patient and contribute to decisions in the treatment and prevention of LUAD patients.
Ovonic threshold switching (OTS) selector has gained lots of attention due to its potential for realization of large density 3-dimensional (3D) stacking memory. In this letter, binary OTS material As
...3
Se
4
has been demonstrated with excellent performance. The OTS material showed outstanding selector performance such as large on-state current (5 mA) and low off-state current (~ 1nA), resulting in a large selectivity of 10
6
. The device endurance can reach 2 × 10
6
times. The ON/OFF switching speed is 12/150 ns, respectively. The bandgap of the amorphous As
3
Se
4
is about 1.55 eV. Combining the X-ray photoelectron spectroscopy and Raman results we found that the main structure motifs are AsSe
3
pyramidal and As
4
Se
3
in the amorphous As
3
Se
4
film. The As
3
Se
4
can be used as a base material for OTS device.
PDF
