In order to investigate the effect of space environmental factors on spacecraft materials, a ground-based simulation facility for space atomic oxygen（AO） irradiation was developed in our laboratory. Some Kapton film...In order to investigate the effect of space environmental factors on spacecraft materials, a ground-based simulation facility for space atomic oxygen（AO） irradiation was developed in our laboratory. Some Kapton film samples were subjected to AO beam generated by this facility. The Kapton films before and after AO exposure were analyzed comparatively using optical microscopy, scanning electronic microscopy, atomic force microscopy, high-precision microbalance, and X-ray photoelectron spectroscopy. The experimental results indicate that the transmittance of Kapton film will be reduced by AO irradiation notably, and its color deepens from pale yellow to brown. Surface roughness of the AO-treated sample is already increased obviously after AO irradiation for 5 hours, and exhibits a flannel-like appearance after 15 hours’ exposure in AO beam. The imide rings and benzene rings in kapton molecule are partially decomposed, and some new bonds form during AO irradiation. The mass loss of kapton film increases linearly with the increase of AO fluence, which is resulted from the formation of volatile products, such as CO, CO2 and NOx. The breakage in structure and degradation in properties of AO-treated Kapton film can be attributed to the integrated effect ofimpaction and oxidization of AO beam. The test results agree well with the space flight experimental data.展开更多
O3-type layered oxides,offering the advantages of high specific capacity and low cost,are currently regarded as one of the most promising cathode materials for sodium-ion batteries(SIBs),demonstrating conside-rable po...O3-type layered oxides,offering the advantages of high specific capacity and low cost,are currently regarded as one of the most promising cathode materials for sodium-ion batteries(SIBs),demonstrating conside-rable potential in energy storage systems.However,undesirable phase transitions and sluggish sodium-ion diffusion severely impede their further development.Herein,synergistic chemical substitution was employed to remarkably enhance cycling stability while simultaneously boosting rate capability.The as-prepared NaNi_(0.289)Fe_(0.284)Mn_(0.283)Cu_(0.097)Mg_(0.046)O_(2)(NFMCM)exhibited exceptional cycling stability with 86.1%capacity retention over 200 cycles at 1 C with an energy density of 400 Wh·kg^(-1),significantly surpassing the pristine Na(NiFeMn)_(1/3)O_(2)(NFM,64.3%),while delivering a remarkable specific capacity exceeding 60 mAh·g^(-1)at an ultrahigh rate of 10 C.Notably,the full cell configured with NFMCM and commercial hard carbon maintains 83.4%capacity retention over 300 cycles(266 Wh·kg^(-1)),highlighting substantial potential for practical implementation.Density functional theory(DFT)calculations reveal that NFMCM possesses an optimized charge environment around oxygen species,where the elevated transition metal sliding energy effectively suppresses the O3-P3 phase transition,thereby optimizing the electrochemical performance.This work provides novel insights into the design principles of O3-type cathode materials for SIBs.展开更多
基金Funded by the Distinguished Young Scholars of NSFC(51125023)the Major State Basic Research Development Programof China(2011CB013405)the Natural Science Foundation of Beijing City(3120001)
文摘In order to investigate the effect of space environmental factors on spacecraft materials, a ground-based simulation facility for space atomic oxygen（AO） irradiation was developed in our laboratory. Some Kapton film samples were subjected to AO beam generated by this facility. The Kapton films before and after AO exposure were analyzed comparatively using optical microscopy, scanning electronic microscopy, atomic force microscopy, high-precision microbalance, and X-ray photoelectron spectroscopy. The experimental results indicate that the transmittance of Kapton film will be reduced by AO irradiation notably, and its color deepens from pale yellow to brown. Surface roughness of the AO-treated sample is already increased obviously after AO irradiation for 5 hours, and exhibits a flannel-like appearance after 15 hours’ exposure in AO beam. The imide rings and benzene rings in kapton molecule are partially decomposed, and some new bonds form during AO irradiation. The mass loss of kapton film increases linearly with the increase of AO fluence, which is resulted from the formation of volatile products, such as CO, CO2 and NOx. The breakage in structure and degradation in properties of AO-treated Kapton film can be attributed to the integrated effect ofimpaction and oxidization of AO beam. The test results agree well with the space flight experimental data.
基金supported by the National Natural Science Foundation of China(Nos.22179077 and 22479091)National Natural Science Foundation Youth Fund(No.22209104)+1 种基金ShangHai Gas Turbine Union Innovation Center(No.GYQ1-2023-1-06)Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University.
文摘O3-type layered oxides,offering the advantages of high specific capacity and low cost,are currently regarded as one of the most promising cathode materials for sodium-ion batteries(SIBs),demonstrating conside-rable potential in energy storage systems.However,undesirable phase transitions and sluggish sodium-ion diffusion severely impede their further development.Herein,synergistic chemical substitution was employed to remarkably enhance cycling stability while simultaneously boosting rate capability.The as-prepared NaNi_(0.289)Fe_(0.284)Mn_(0.283)Cu_(0.097)Mg_(0.046)O_(2)(NFMCM)exhibited exceptional cycling stability with 86.1%capacity retention over 200 cycles at 1 C with an energy density of 400 Wh·kg^(-1),significantly surpassing the pristine Na(NiFeMn)_(1/3)O_(2)(NFM,64.3%),while delivering a remarkable specific capacity exceeding 60 mAh·g^(-1)at an ultrahigh rate of 10 C.Notably,the full cell configured with NFMCM and commercial hard carbon maintains 83.4%capacity retention over 300 cycles(266 Wh·kg^(-1)),highlighting substantial potential for practical implementation.Density functional theory(DFT)calculations reveal that NFMCM possesses an optimized charge environment around oxygen species,where the elevated transition metal sliding energy effectively suppresses the O3-P3 phase transition,thereby optimizing the electrochemical performance.This work provides novel insights into the design principles of O3-type cathode materials for SIBs.
