ABSTRACT
Controlled aggregation is of great significance in designing nanodevices with high electrochemical performance. In this study, an in situ aggregation strategy with cyclodextrin polymer (CDP) was employed to prepare polyaniline (PANI)/MXene (MX) composites. MXene served as a two-dimensional structure template. Due to supramolecular interactions, CDP could be controllably modified with PANI layers, effectively preventing the self-polymerization of PANI. As a result, this integration facilitated a more uniform growth of PANI on MXene and further improved the capacitance performance of CDP-MX/PA. In a three-electrode system, the specific capacitance of MX/PA at 1 A g-1 was 460.8 F g-1, which increased to 523.8 F g-1 after CDP-induced growth. CDP-MX/PA exhibited a high energy density of 27.7 W h kg-1 at a power density of 700 W kg-1. This suggests that the synthetic strategy employed in this study holds promise in providing robust support for the preparation of high-performance energy-storage device.
ABSTRACT
In this study, a strategy for the rapid and simple preparation of porous carbon (PC) using the microwave method was proposed. Oxygen-rich PC was synthesized by microwave irradiation in air, where potassium citrate and ZnCl2 served as the carbon source and microwave absorber, respectively. ZnCl2 achieves microwave absorption through dipole rotation, which uses ion conduction to convert heat energy in the reaction system. In addition, potassium salt etching improved the porosity of PCs. The PC prepared under optimal conditions had a large specific surface area (902 m2·g-1) and exhibited a significant specific capacitance (380 F·g-1) in the three-electrode system at 1 A·g-1. The energy and power densities of the assembled symmetrical supercapacitor device based on PC-375W-0.4 were 32.7 W·h·kg-1 and 0.65 kW·kg-1, respectively, at a current density of 1 A·g-1. Even after 5000 cycles at 5 A·g-1 current density, the excellent cycle life retained 94% of its initial capacitance.
ABSTRACT
By introducing a heteroatom into carbon material, an effective improvement in capacitance can be realized owing to surface oxidation and reduction reactions of pseudocapacitors. Herein, a simple one-pot carbonization activation method was proposed to convert potassium citrate into three-dimensional interconnected porous carbon (PC). Then, an effective double heteroatom doping method by thiourea was used to prepare nitrogen-sulfur-doped PC (N,S-PC). This porous structure facilitates the storage of a large number of ions and reduces their diffusion path. The synthesized N,S-PC nanomaterial has a capacitance of 674 F/g at 1 A/g in a 1 M H2SO4 electrolyte, can retain 94.41% of the initial capacitance after 10â¯000 cycles at 5 A/g, and has a long cycle life. More importantly, a symmetric supercapacitor assembled with this material can exhibit an energy density of up to 32.6 (W·h)/kg at a high-power density of 750 W/kg. This is due to the high performance of N,S-PC in supercapacitor electrode materials.
ABSTRACT
The present study aimed at exploring the therapeutic potential of standard extract of Bombax ceiba L. leaves (BCE) in type 2 diabetic mellitus (T2DM). Oral administration of BCE at doses of 70, 140, and 280 mg·kg-1, to the normal rats and the high-fat-diet- and streptozotocin-induced T2DM rats were carried out. Effects of BCE on blood glucose, body weight, and a range of serum biochemical parameters were tested, and histopathological observation of pancreatic tissues was also performed. HPLC-ESI-Q/TOF-MS/MS analysis indicated that the chemical composition of BCE mainly contained mangiferin, isoorientin, vitexin, isomangiferin, isovitexin, quercetin hexoside, 2'-trans-O-cumaroyl mangiferin, and nigricanside. BCE caused a significant decrease in the concentrations of fasting blood glucose, glycosylated hemoglobin, total cholesterol, triglyceride, low density lipoprotein-cholesterol, serum insulin, and malondialdehyde, and increases in oral glucose tolerance, high density lipoprotein-cholesterol, and superoxide dismutase in the T2DM model rats. Moreover, considerable pancreatic ß-cells protection effect and stimulation of insulin secretion from the remaining pancreatic ß-cells could be observed after BCE treatment. The results indicated that BCE exhibited an excellent hypoglycemic activity, and alleviated dyslipidemia which is associated with T2DM. Antioxidant activity and protecting pancreatic ß-cells are the possible mechanisms involved in anti-diabetic activity of BCE.
