Mechanism of high-concentration electrolyte inhibiting the destructive effect of Mn(Ⅱ)on the performance of lithium-ion batteries

By optimizing electrolyte formulation to inhibit the deposition of transition metal ions(TMIs) on the surface of the graphite anode is an effective way to improve the electrochemical performance of lithium-ion batteries.At present,it is generally believed the formation of an effective interfacial film on the surface of the anode electrode is the leading factor in reducing the dissolution of TMIs and prevent TMIs from being embedded in the electrode.It ignores the influence of the solvation structures in the electrolyte system with different composition,and is not conducive to the design of the electrolyte formulation from the perspective of changing the concentration and the preferred solvent to inhibit the degradation of battery performance caused by TMIs deposition.In this work,by analyzing the special solvation structures of the high-concentra tion electrolyte,we study the main reason why high-concentration electrolyte inhibits the destructive effect of Mn(Ⅱ) on the electrochemical performance of LIBs.By combining the potentialresolved in-situ electrochemical impedance spectroscopy technology(PRIs-EIS) and density functional theory(DFT) calculation,we find that Mn(Ⅱ) mainly exists in the form of contact ions pairs(CIPs) and aggregates(AGGs) in high-concentration electrolyte.These solvation structures can reduce the destructive effect of Mn(Ⅱ) on battery performance from two aspects:on the one hand,it can rise the lowest unoccupied orbital(LUMO) value of the solvation structures of Mn(Ⅱ),thereby reducing the chance of its reduction;on the other hand,the decrease of Mn2+ions reduction can reduce the deposition of metallic manganese in the solid electrolyte interphase(SEI),thereby avoiding the continuous growth of the SEI.This study can be provided inspiration for the design of electrolytes to inhibit the destructive effect of TMls on LIBs.

玻色-爱因斯坦凝聚中的非厄米趋肤效应

研究了超冷原子玻色-爱因斯坦凝聚体中的非厄米趋肤效应。该效应源于非厄米自旋轨道耦合以及光诱导原子数损耗的共同作用。通过周期边界下体系能谱的缠绕,开边界下本征态向边界的积累,以及体系内部波包的单向传播,验证了非厄米趋肤效应的存在。其中单向传播的体动力学尤其适于该效应的实验探测。进一步通过非厄米Gross-Pitaevskii方程,研究了在相互作用与束缚势的作用下非厄米趋肤效应的性质。以上结果说明,非厄米趋肤效应及其在体系拓扑、动力学等方面的深刻影响,可以在当前冷原子实验平台上进行研究。

Quantum Droplets in a Mixture of Bose–Fermi Superfluids

We study the formation of quantum droplets in the mixture of a single-component Bose–Einstein condensate(BEC),and a two-species Fermi superfluid across a wide Feshbach resonance.With repulsive boson-boson and attractive boson-fermion interactions,we show that quantum droplets can be stabilized by attractive fermionfermion interactions on the Bardeen–Cooper–Schrieffer(BCS)side of the resonance,and can also exist in the deep BEC regime under weak boson-fermion interactions.We map out the phase diagram for stable droplets with respect to the boson-boson and boson-fermion interactions,and discuss the role of different types of quantum fluctuations in the relevant regions of the BCS-BEC crossover.Our work reveals the impact of fermion pairing on the formation of quantum droplets in Bose–Fermi mixtures,and provides a useful guide for future experiments.

Totally Asymmetric Simple Exclusion Process under Exit Control Feedback Policy

The effect of the exit control feedback policy on traffic flow was investigated in this paper.Here,the exit rate(β)can be defined as a function of the hopping rate(p),the current(J)and the bulk density(ρ_(bulk)),which can be rewritten as β=p-J/ρ_(bulk).A model based on normal totally asymmetric simple exclusion process(TASEP)has been analyzed by mean field approach.It is found that a phase transformation point exists in the phase diagram,which is determined by p.In addition,the traffic flow of the system achieves maximum current when the exit rate maintains itself atβ=p/2 for all other phases except the low density(LD)phase.The result implies that we can use the control feedback policy to make the traffic flow reach the maximum value when the traffic system is in the traffic jam status.

3D-printed hierarchical porous and multidimensional conductive network based on conducting polymer/graphene oxide

Designing ultrathick and hierarchical electrodes is effective to deal with the challenge of high areal capacity and high power density for lithium-ion batteries(LIBs)manufacturing.Here,a thick electrode with hierarchical porous and multidimensional conductive network is fabricated by 3D printing tech-nology,in which both the conducting polymer of poly(3,4-ethylene dioxythiophene):polystyrene sul-fonate(PEDOT:PSS)and graphene oxide(GO)play the dual roles as binders and conductive agents.As a consequence,the 3D-printed thick electrode(~900 mm)with a mass loading of~47 mg/cm^(2) exhibits a good rate capability of 122 mA·h/g at 2 C,a high areal capacity of up to 5.8 mA·h/cm^(2),and stable cycling performance of~95%capacity retention after 100 cycles.Moreover,the C-O-S bond is further confirmed by the spectral analysis and the DFT calculation,which not only hinders the stack of nanosheets but enhances the mechanical stability and electronic conductivity of electrodes.A stable covalent multidi-mensional conductive network constructed by 3D-printing technology provides a new design strategy to improve the performance of LIBs.

Macroporous-mesoporous C-,S-,N-doped titania microspheres via the polyHIPE microspheres templates

Doping and increasing specific surface area by forming highly porous structures are two effective ways to enhance the photocatalytic performances of TiO_(2) particles.He re for the first time,we report a new facile method to prepare the macroporous-mesoporous C-,S-,N-doped TiO_(2)(C/S/N-TiO_(2))microspheres via polyHIPE microsphe res as templates.The chemical and crystalline structure s of these hierarchical porous TiO_(2) microspheres are analyzed with FTIR,XPS,EDS,and XRD.The macroporous-mesoporous structures are confirmed with SEM observation and BET analysis.UV-vis DRS spectra analysis shows that the band gaps of C doped TiO_(2),C/N doped TiO_(2),C/S doped TiO_(2) and C/S/N doped TiO_(2) are estimated to be 3.07,3.01,2.94 and 2.81 eV,respectively,which are significantly narrower than that of TiO_(2) nanoparticles(3.23 eV).Photoluminescence spectra demonstrate that the recombination of electrons and holes in these macroporous-mesoporous TiO_(2) microspheres is also suppressed.The hierarchical porous C/S/N-TiO_(2) microspheres show high visible-light catalytic efficiency and excellent cycling stability to degrade RhB dye.

Fermion superfluid with hybridized s-and p-wave pairings

Ever since the pioneering work of Bardeen, Cooper and Schrieffer in the 1950 s, exploring novel pairing mechanisms for fermion superfluids has become one of the central tasks in modern physics. Here, we investigate a new type of fermion superfluid with hybridized s-and p-wave pairings in an ultracold spin-1/2 Fermi gas. Its occurrence is facilitated by the co-existence of comparable s-and p-wave interactions, which is realizable in a two-component 40 K Fermi gas with close-by s-and p-wave Feshbach resonances. The hybridized superfluid state is stable over a considerable parameter region on the phase diagram, and can lead to intriguing patterns of spin densities and pairing fields in momentum space. In particular, it can induce a phase-locked p-wave pairing in the fermion species that has no p-wave interactions. The hybridized nature of this novel superfluid can also be confirmed by measuring the s-and p-wave contacts, which can be extracted from the high-momentum tail of the momentum distribution of each spin component. These results enrich our knowledge of pairing superfluidity in Fermi systems, and open the avenue for achieving novel fermion superfluids with multiple partial-wave scatterings in cold atomic gases.