Achieving a superior Na storage performance of Fe-based Prussian blue cathode by coating perylene tetracarboxylic dianhydride amine

Fe-based Prussian blue(Fe-PB)cathode material shows great application potential in sodium(Na)-ion batteries due to its high theoretical capacity,long cycle life,low cost,and simple preparation process.However,the crystalline water and vacancies of Fe-PB lattice,the low electrical conductivity,and the dissolution of metal ions lead to limited capacity and poor cycling stability.In this work,a perylene tetracarboxylic dianhydride amine(PTCDA)coating layer is successfully fabricated on the surface of Fe-PB by a liquid-phase method.The aminated PTCDA(PTCA)coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies,which avoids the erosion of Fe-PB by electrolyte.Consequently,the PTCA layer reduces the charge transfer resistance,enhances the Na-ion diffusion coefficient,and improves the structure stability.The PTCA-coated Fe-PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g^(−1) at 100 mA g^(−1).Long cycling tests exhibit minimal capacity decay of 0.027%per cycle over 1000 cycles at 1 A g^(−1).Therefore,this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe-PB,which can potentially serve as a universal electrode coating strategy for Na-ion batteries.

Ternary Ni-based Prussian blue analogue with superior sodium storage performance induced by synergistic effect of Co and Fe

Prussian blue analogue Na2Ni[Fe(CN)6](Ni-PB)has been widely studied as a cathode material for sodium-ion battery due to its excellent cycling performance.However,Ni-PB has a low theoretical capacity of 85 mAh g^(−1) because of the electrochemical inertness of Ni.Herein,ternary Ni-PB is successfully synthesized by double doping with Co and Fe at Ni-site,and the effect of doping with Co and Fe on the electrochemical performance of Ni-PB is systematically investigated through theoretical calculations and electrochemical tests.The first principles calculations confirm that double doping with Co and Fe can significantly reduce the energy barrier and bandgap of Ni-PB.X-ray diffraction and composition analysis results indicate that ternary NiCoFe-PB composite not only has good crystallinity and high Na content but also has low defects and crystal water.Electrochemical tests reveal that,besides the capacity contribution of high-spin Co/Fe and low-spin Fe,Co-doping enhances the electrochemical activity of low-spin Fe and Fe-doping improves the activity of high-spin Co;moreover,double doping can decrease the diffusion resistance of Na+ions through solid electrolyte interface film,accelerate the kinetics for both ion diffusion process and Faradic reaction,and increase active sites.Under the synergistic effect of Co and Fe,this ternary NiCoFe-PB exhibits outstanding electrochemical performance with a high initial discharge capacity of 120.4 mAh g^(−1) at 20mA g^(−1) and an extremely low capacity fading rate of 0.0044%per cycle at a high current density of 2 A g^(−1) even after 10,000 cycles,showing great application potential of ternary NiCoFe-PB in the field of large-scale energy storage.

Stat5^(−/−)CD4^(+)T cells elicit anti-melanoma effect by CD4^(+)T cell remolding and Notch1 activation

Signal transducers and activators of transcription 5(Stat5)is known to engage in regulating the differentiation and effector function of various subsets of T helper cells.However,how Stat5 regulates the antitumor activity of tumor-infiltrating CD4^(+)T cells is largely unknown.Here,we showed that mice with specific deletion of Stat5 in CD4^(+)T cells were less susceptible to developing subcutaneous and lung metastatic B16 melanoma with CD4^(+)tumor-infiltrating lymphocytes(TILs)remolding.Especially,we confirmed that Stat5-deficient CD4^(+)naïve T cells were prone to polarization of two subtypes of Th17 cells:IFN-γ^(+)and IFN-γ^(-)Th17 cells,which exhibited increased anti-melanoma activity through enhanced activation of Notch1 pathway compared with wild type Th17 cells.Our study therefore revealed a novel function of Stat5 in regulating tumor-specific Th17 cell differentiation and function in melanoma.This study also provided a new possibility for targeting Stat5 and other Th17-associated pathways to develop novel immunotherapies for melanoma patients.