High-frequency supercapacitors with phosphorus-doped Ketjen black

Compact supercapacitors(SCs)have attracted attention for their great potential to replace bulky aluminum electrolytic capacitors(AECs)in alternating current(AC)line filtering applications.Herein,the fabrication of a high-frequency SC is reported using Ketjen black(KB)nanoparticles doped with phosphorus(P)to achieve a high areal capacitance of up to 2.26 mF cm^(-2)along with a high-rate capability,with a phase angle of-80.2°at 120 Hz.The high performance of the phosphorus-doped KB(designated PKB)SC with a 6 M KOH aqueous electrolyte is associated with its increased surface wettability and additional capacitive sites provided by the P-doping.Density functional theory(DFT)calculations further indicate that the P-doping enhances the interactions between the electrolyte ions and the carbon surface,thus leading to an improved electrochemical performance.These results suggest that the P-doped carbonbased SC could be highly favored in replacing conventional AECs in various high-frequency electronic devices.

Improvement of Water and Wastewater Treatment Process Using Various Sound Waves—A Consideration from the Viewpoint of Frequency

Application of sound waves is one of the novel techniques for the improvement of water treatment process. In this study, various sound waves such as 1) ultrasonic wave, 2) music box, and 3) windbell were irradiated to water and wastewater for removing contaminants such as nitrate, phosphorus and BOD/COD. As a result, a possibility of improvement of water and wastewater treatment process using sound waves with various frequencies was proposed.

Structural Characters and Isolated Stability of Phosphorus Polyanions

The optimized geometries at the RHF/6-311++G** level, the relatively stable energy at the MPW1PW91/6-311++G** level and the structural characters of anions have been acquired, indicating the stability is related to the chemical bonding of μ2?P atoms and the distri- bution of negative charges. The configurations of cage units P8 4- and P9 5- are stable due to the less torsion, but their ES values are relatively higher than that of P7 3- with more μ2?P atoms and the isolated stability is lower than that of P7 . They potentially play an important role as intermediate 3- in chemical reaction of producing complicated polyphosphides. Based on the related electronic properties, a stable polyanion must have low valence electron concentration, no (μ2?P)?(μ2?P) bond and a little dispersive charge. The earmark IR frequencies of cage units have been assigned to the vibration models in the end.

Influence of Phosphorus Content and Magnetic Annealing on Soft Magnetic Properties of Electrodeposited Amorphous FeMnP Alloy Films

In this work, we investigated the influence of phosphorus and magnetic anneal on the soft magnetic properties of electrodeposited FeMnP alloy films prepared by changing sodium hypophosphite concentrations. X-ray diffraction radiation patterns showed an amorphous structure of electrodeposited alloy films. The saturation magnetization and coercivity value decreased from 586 emu/cc to 346 emu/cc, and 52 Oe to 18 Oe, with the P content increased, respectively. The absorption resonance peak became broad as the P content increased, and the natural resonance frequency decreased from 1.8 GHz to 0.6 GHz, with the P content increasing. Magnetic annealing of samples reduced the magnetic damping, and natural resonance frequency increased by about 1.8 GHz and 3.5 GHz for the sample with lower and higher P content. The film structure with lower P content changed at 300˚C, while the structure remains unchanged for the films with higher P content. Thus, the crystallization temperature could depend on the P content in the film. FeMnP alloy films could be used in high-frequency devices.