High Power- and Energy-Density Supercapacitors through the Chlorine Respiration Mechanism.

Supercapacitor represents an important electrical energy storage technology with high-power performance and superior cyclability. However, currently commercialized supercapacitors still suffer limited energy densities. Here we report an unprecedentedly respiring supercapacitor with chlorine gas iteratively re-inspires in porous carbon materials, that improves the energy density by orders of magnitude. Both electrochemical results and theoretical calculations show that porous carbon with pore size around 3 nm delivers the best chlorine evolution and adsorption performance. The respiring supercapacitor with multi-wall carbon nanotube as the cathode and NaTi2 (PO4 )3 as the anode can store specific energy of 33 Wh kg-1 with negligible capacity loss over 30 000 cycles. The energy density can be further improved to 53 Wh kg-1 by replacing NaTi2 (PO4 )3 with zinc anode. Furthermore, thanks to the extraordinary reaction kinetics of chlorine gas, this respiring supercapacitor performs an extremely high-power density of 50 000 W kg-1 .

Prediction of two-dimensional ferromagnetic ferroelectric VOF2 monolayer.

Nowadays, designing and searching for materials with multiple functional characteristics are the keys to achieving high-performance electronic devices. Among many candidates, two-dimensional multiferroic materials have great potential to be applied in highly integrated magnetoelectric devices, such as high-density non-volatile memories. Here, we predict a two-dimensional material, VOF2 monolayer, to possess intrinsic ferroelectric and ferromagnetic properties. The VOF2 monolayer owns the largest in-plane ferroelectric polarization (332 pC m-1) in the family of VOX2 (X: halogen) oxyhalides. Different from other VOX2 monolayers whose magnetic ground states are antiferromagnetic or noncollinear spiral textures, the VOF2 monolayer owns a robust ferromagnetic ground state, which is rare but highly desirable. Our theoretical prediction provides a good candidate and starting point for the further pursuit of more two-dimensional multiferroic materials with high-performance magnetoelectricity.

The study on pyrolysis of oil-based drilling cuttings by microwave and electric heating.

In this paper, the following questions were investigated: the proportion of mass loss, the mass fraction of oil, the structure, composition and ultimate analysis of solid residues and gas products. By comparing the treatment effect of using both microwave and electric as the source of heat to dispose the oil-based drilling cuttings (OBDC), the advantages of microwave heating treatment were demonstrated. Meanwhile, the composition of liquid products by microwave pyrolysis was analyzed. The results show that the microwave heating is better than electric heating and the former can promote the pyrolysis of petroleum hydrocarbons. The results of component analysis of the liquid products from OBDC by microwave pyrolysis show that C12∼C20 components pyrolyze at 500 °C. At the same time, a mass of C21∼C24 components volatilize. At the temperature above 500 °C, the thermal cracking reactions of >C25 components occur and a maximum content of paraffin in liquid products is obtained. As the temperature increases, the components obtained by pyrolysis become more and more complex.

High thermal stability and low power dissipation PCM with nanoscale oxygen-doped SS thin film.

To improve thermal stability and reduce power dissipation of phase-change memory (PCM), the oxygen-doped Sn15Sb85 (SS) thin film is proposed by magnetron sputtering in this study. Comparing to undoped Sn15Sb85(SS), the oxygen-doped-SS thin film has superior thermal stability and better data retention. Meanwhile, the electrical conductivity of crystallisation oxygen-doped-SS thin film is also lower than that of SS, which means its less power consuming in PCM. The electrical conductivity ratio between amorphous and crystalline states for oxygen-doped SS reaches up to two orders of magnitude. After oxygen doping, the root-mean-square surface roughness from amorphous (0.29 nm) to crystalline (0.46 nm) state for oxygen-doped-SS thin films becomes smaller. The switching time of amorphisation process for the oxygen-doped-SS thin film (∼2.07 ns) is shorter than Ge2Sb2Te5 (GST) (∼3.05 ns). X-ray diffractometer is recorded to investigate the change of crystalline structure. Thus, the authors infer that oxygen-doped SS is a promising phase-change thin film for PCM.