Rational design of nanoarray structures for lithium-sulfur batteries:recent advances and future prospects

Lithium-sulfur(Li-S)batteries are considered as promising candidates for future-generation energy storage systems due to their prominent theoretical energy density.However,their application is still hindered by several critical issues,e.g.,the low conductivity of sulfur species,the shuttling effects of soluble lithium polysulfides,volumetric expansion,sluggish redox kinetics,and uncontrollable Li dendritic formation.Considerable research efforts have been devoted to breaking through the obstacles that are preventing Li-S batteries from realizing practical application.Recently,benefiting from the no additives/binders,buffer of volume change,high sulfur loading and suppression of lithium dendrites,nanoarray(NA)structures have have emerged as efficient and durable electrodes in Li-S batteries.In this work,recent advances in the design,synthesis and application of NA structures in Li-S batteries are reviewed.First,the multifunctional merits and typical synthetic strategies of employing NA structure electrodes for Li-S batteries are outlined.Second,the applications of NA structures in Li-S batteries are discussed comprehensively.Finally,the challenge and rational design of NA structure for Li-S batteries are analyzed in depth,with the aim of providing promising orientations for the commercialization of high-energy-density Li-S batteries.

Simulation of f-d transition using the extended crystal-field model:parameter dependent study for Er^(3+) in various hosts

The 4f-5d transitions of Er3+ ions doped in crystals were widely studi ed due to their potential applications in quantum cutting phosphors and VUV lase rs,etc.The theory to do the calculations of 4f-5d transitions and various rela ted aspects,such as the ways to determining various parameters,were summarized .The impacts of various interactions on the spectra were also demonstrated clea rly with Er3+ ions in crystals CaF2 and LiYF4.Predicted results were compared w ith measured spectra.