The structure of an electronegative magnetized plasma sheath with non-extensive electron distribution

In this paper, an electronegative magnetized plasma sheath model with non-extensive electron distribution is established, and the Bohm criterion affected by the non-extensive parameter q is theoretically derived. The ion Mach number varies with q. The numerical simulation results show that compared with electronegative magnetized plasma sheath with Maxwell distribution(q=1), the sheath structures with super-extensive distribution(q<1) and sub-extensive distribution(q>1) are different. The physical quantities including the sheath potential distribution, ion density distribution, the electron density distribution, negative ion density distribution and the net space charge density distribution are discussed. It is shown that the non-extensive parameter q has a significant influence on the structure of the electronegative magnetized plasma sheath. Due to the Lorentz force, both the magnitude and the angle of the magnetic field affect the structure of the sheath, whether the electrons are Maxwell distributed or non-extensively distributed.

Recent advances in copper-based materials for robust lithium polysulfides adsorption and catalytic conversion

Lithium-sulfur(Li-S) batteries are considered one of the most promising next-generation secondary batteries owing to their ultrahigh theoretical energy density.However,practical applications are hindered by the shuttle effect of soluble lithium polysulfides(Li PSs) and sluggish redox kinetics,which result in low active material utilization and poor cycling stability.Various copper-based materials have been used to inhibit the shuttle effect of Li PSs,owing to the strong anchoring effect caused by the lithiophilic/sulphilic sites and the accelerated conversion kinetics caused by excellent catalytic activity.This study briefly introduces the working principles of Li-S batteries,followed by a summary of the synthetic methods for copper-based materials.Moreover,the recent research progress in the utilization of various copper-based materials in cathodes and separators of Li-S batteries,including copper oxides,copper sulfides,copper phosphides,copper selenides,copper-based metal-organic frameworks(MOFs),and copper single-atom,are systematically summarized.Subsequently,three strategies to improve the electrochemical performance of copper-based materials through defect engineering,morphology regulation,and synergistic effect of different components are presented.Finally,our perspectives on the future development of copper-based materials are presented,highlighting the major challenges in the rational design and synthesis of high-performance Li-S batteries.