Electrocatalytic and stoichiometric reactivity of 2D layered siloxene for high-energy-dense lithium-sulfur batteries

Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration.To mitigate this challenge,two-dimensional(2D)siloxene(2DSi),a Si-based analog of graphene,is utilized as an additive for sulfur cathodes.The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin-layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi.The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator,secures the intercalation pathway,and reveals Lewis acidic sites within the siloxene galleries.The 2DSi utilizes the corresponding in-situ-formed electrocatalyst,the 2D confinement effect of the layered structure,and the surface affinity based on Lewis acid-base interaction to improve the energy density of 2DSi-based LSB cells.Combined with the commercial carbon-based current collector,2DSi-based LSB cells achieve a volumetric energy density of 612 Wh Lcell^(−1) at 1 mA cm^(−2) with minor degradation of 0.17%per cycle,which rivals those of state-of-the-art LSBs.This study presents a method for the industrial production of high-energy-dense LSBs.

Thick free-standing electrode based on carbon-carbon nitride microspheres with large mesopores for high-energy-density lithium-sulfur batteries

The development of sulfur cathodes with high areal capacity and high energy density is crucial for the practical application of lithium-sulfur batteries(LSBs).LSBs can be built by employing(ultra)high-loading sulfur cathodes,which have rarely been realized due to massive passivation and shuttling.Herein,microspheres of a carbon-carbon nitride composite(C@CN)with large mesopores are fabricated via molecular cooperative assembly.Using the C@CN-based electrodes,the effects of the large mesopores and N-functional groups on the electrochemical behavior of sulfur in LSB cells are thoroughly investigated under ultrahigh sulfur-loading conditions(>15 mgS cm^(-2)).Furthermore,for high-energy-density LSBs,the C@CN powders are pelletized into a thick free-standing electrode(thickness:500^m;diameter:11 mm)via a simple briquette process;here,the total amount of energy stored by the LSB cells is 39 mWh,corresponding to a volumetric energy density of 440 Wh L-1 with an areal capacity of 24.9 and 17.5 mAh cm^(-2) at 0.47 and 4.7 mA cm^(-2),respectively(at 24mgS cm^(-2)).These results have significantly surpassed most recent records due to the synergy among the large mesopores,(poly)sulfide-philic surfaces,and thick electrodes.The developed strategy with its potential for scale-up successfully fills the gap between laboratory-scale cells and practical cells without sacrificing the high areal capacity and high energy density,providing a solid foundation for the development of practical LSBs.

Bisphenol A in combination with TNF-a selectively induces Th2 cell-promoting dendritic cells in vitro with an estrogen-like activity

Bisphenol A(BPA)is a monomer used in manufacturing a wide range of chemical products,including epoxy resins and polycarbonate.BPA,an important endocrine disrupting chemical that exerts estrogen-like activities,is detectable at nanomolar levels in human serum worldwide.The pregnancy associated doses of 17b-estradiol(E2)plus tumor-necrosis factor-a(TNF-a)induce distorted maturation of human dendritic cells(DCs)that result in an increased capacity to induce T helper(Th)2 responses.The current study demonstrated that the presence of BPA during DC maturation influences the function of human DCs,thereby polarizing the subsequent Th response.In the presence of TNF-a,BPA treatment enhanced the expression of CC chemokine ligand 1(CCL1)in DCs.In addition,DCs exposed to BPA/TNF-a produced higher levels of IL-10 relative to those of IL-12p70 on CD40 ligation,and preferentially induced Th2 deviation.BPA exerts the same effect with E2 at the same dose(0.01–0.1 mM)with regard to DC-mediated Th2 polarization.These findings imply that DCs exposed to BPA will provide one of the initial signals driving the development and perpetuation of Th2-dominated immune response in allergic reactions.