Sluggish conversion reaction kinetics and spontaneous shuttle effect of lithium polysulfides(LiPSs)are deemed as the two big mountains that hinder the practical application of lithium-sulfur batteries(LSBs).Herein,dua...Sluggish conversion reaction kinetics and spontaneous shuttle effect of lithium polysulfides(LiPSs)are deemed as the two big mountains that hinder the practical application of lithium-sulfur batteries(LSBs).Herein,dual-defect engineering strategy is implemented by introducing boron-doping and phosphorusvacancy sites with MoP@NC composite as the precursor.Based on the experimental characterizations and theoretical calculations,B-MoP_(1-x)@NC-based electrode presents low oxidation potential,high lithium diffusivity,small Tafel slope and strong adsorption capability for polysulfides,which is beneficial to enhance the adsorption capability for LiPSs,reduce the lithium diffusion energy barriers and Gibbs free energy for the conversion reactions of LiPSs.As demonstrated,the corresponding Li-S/B-MoP1-x@NC batteries can remain high reversible capacity of 753 mAh/g at 0.5 C after 300 cycles,and keep a stable capacity of 520 mAh/g at 0.5 C after 100 cycles even at the high-loading content of 5.1mg/cm^(2).According to the results of in-situ UV–vis spectra,the satisfactory battery performance majorly originates from the existence of dual-defect characteristics in B-MoP1-x@NC catalyst,which effectively promotes the conversion reaction kinetics of LiPSs,and restrains the shuttle behavior of LiPSs.The key ideas of this work will enlighten the development of catalytic cathode materials for sulfur-based secondary batteries.展开更多
Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategie...Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.展开更多
Photocatalytic hydrogen evolution(PHE)is one of the most promising methods for clean energy production.However,current photocatalysts are still challenged by limited light absorption and rapid recombination of photoge...Photocatalytic hydrogen evolution(PHE)is one of the most promising methods for clean energy production.However,current photocatalysts are still challenged by limited light absorption and rapid recombination of photogenerated carriers.Constructing defects can effectively broaden light absorption and promote charge separation and transfer.The interface between heterogeneous catalysts is prone to generating multi-component active centers to facilitate the activation of reactants for enhanced catalytic activity.In this report,the combination of defective TiO_(2)and ZnIn_(2)S_(4)of sulfur-rich vacancies(TiO_(2)@ZIS)was developed,which achieved an optimized PHE rate of 9.63 mmol g^(-1)h^(-1).After loading 1.0 wt%Pt cocatalyst,TiO_(2)@ZIS exhibits the apparently-raised PHE rate of 83.41 mmol g^(-1)h^(-1)in the presence of triethanolamine(TEOA)as the sacrificial agent.Theoretical calculation and experimental results reveal that the remarkable hydrogen(H_(2))evolution performance is contributed by the unique Z-scheme charge transfer pathway,which reduces energy loss during charge transfer and facilitates the kinetics of surface H_(2)evolution.This report provides valuable insights into designing and engineering defective materials for solar-driven energy conversion.展开更多
针对焊接缺陷具有多尺度,形态复杂和易受背景干扰等特点,提出一种基于YOLOv8n的焊接缺陷检测算法YOLOSBRS.首先利用空间和通道重建卷积(spatial and channel reconstruction convolution,SCConv)卷积改进主干网络的C2f模块;同时设计一...针对焊接缺陷具有多尺度,形态复杂和易受背景干扰等特点,提出一种基于YOLOv8n的焊接缺陷检测算法YOLOSBRS.首先利用空间和通道重建卷积(spatial and channel reconstruction convolution,SCConv)卷积改进主干网络的C2f模块;同时设计一种具有双层路由注意力机制的空间金字塔快速平均池化(spatial pyramid pooling fast average pooling with biformer attention module, SPPF_ABF)模块,将原始SPPF模块的最大池化替换为平均池化操作,并引入双层路由Transformer注意力机制;其次采用重参数化广义特征金字塔网络(reparameterized generalized feature pyramid network,RepGFPN)优化特征融合部分;最后,基于参数共享原理及引入联合空间到深度层和非跨步卷积层模块(a module combining space-to-depth and non-strided convolutional layers,SPD_Conv)改进检测头,实现轻量化的同时提升网络对复杂缺陷的检测能力.试验结果表明,改进后算法的精度和交并比为50%的平均精度均值(mean average precision at 50%intersection over union,mAP50)分别提高3.1%和2.8%,为焊接缺陷检测提供一种高效且可行的解决方案.展开更多
基金financial support from National Natural Science Foundation of China(No.52101250)Hebei Provincial Natural Science Foundation(Nos.E2021208031 and B2021208069)+6 种基金S&T program of Hebei(Nos.215A4401D and 225A4404D)Research Fund of the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202315)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)partially supported by the Pico Election Microscopy Center of Hainan UniversityFundamental Research Funds for the Hebei University(No.2021YWF11)Science Research Project of Hebei Education Department(No.QN2024087)Xingtai City Natural Science Foundation(No.2023ZZ027)
文摘Sluggish conversion reaction kinetics and spontaneous shuttle effect of lithium polysulfides(LiPSs)are deemed as the two big mountains that hinder the practical application of lithium-sulfur batteries(LSBs).Herein,dual-defect engineering strategy is implemented by introducing boron-doping and phosphorusvacancy sites with MoP@NC composite as the precursor.Based on the experimental characterizations and theoretical calculations,B-MoP_(1-x)@NC-based electrode presents low oxidation potential,high lithium diffusivity,small Tafel slope and strong adsorption capability for polysulfides,which is beneficial to enhance the adsorption capability for LiPSs,reduce the lithium diffusion energy barriers and Gibbs free energy for the conversion reactions of LiPSs.As demonstrated,the corresponding Li-S/B-MoP1-x@NC batteries can remain high reversible capacity of 753 mAh/g at 0.5 C after 300 cycles,and keep a stable capacity of 520 mAh/g at 0.5 C after 100 cycles even at the high-loading content of 5.1mg/cm^(2).According to the results of in-situ UV–vis spectra,the satisfactory battery performance majorly originates from the existence of dual-defect characteristics in B-MoP1-x@NC catalyst,which effectively promotes the conversion reaction kinetics of LiPSs,and restrains the shuttle behavior of LiPSs.The key ideas of this work will enlighten the development of catalytic cathode materials for sulfur-based secondary batteries.
基金supported by the National Natural Science Foundation of China(52222407).
文摘Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.
基金National Key Research and Development Program of China(2022YFC2105800)National Natural Science Foundation of China(22301099 and 22279041)+2 种基金the 111 Project(B17020)the Jilin Province Science and Technology Development Program(20250102085JC)the Australian Research Council(ARC)through the Discovery Project programs(FT230100192)。
文摘Photocatalytic hydrogen evolution(PHE)is one of the most promising methods for clean energy production.However,current photocatalysts are still challenged by limited light absorption and rapid recombination of photogenerated carriers.Constructing defects can effectively broaden light absorption and promote charge separation and transfer.The interface between heterogeneous catalysts is prone to generating multi-component active centers to facilitate the activation of reactants for enhanced catalytic activity.In this report,the combination of defective TiO_(2)and ZnIn_(2)S_(4)of sulfur-rich vacancies(TiO_(2)@ZIS)was developed,which achieved an optimized PHE rate of 9.63 mmol g^(-1)h^(-1).After loading 1.0 wt%Pt cocatalyst,TiO_(2)@ZIS exhibits the apparently-raised PHE rate of 83.41 mmol g^(-1)h^(-1)in the presence of triethanolamine(TEOA)as the sacrificial agent.Theoretical calculation and experimental results reveal that the remarkable hydrogen(H_(2))evolution performance is contributed by the unique Z-scheme charge transfer pathway,which reduces energy loss during charge transfer and facilitates the kinetics of surface H_(2)evolution.This report provides valuable insights into designing and engineering defective materials for solar-driven energy conversion.
文摘针对焊接缺陷具有多尺度,形态复杂和易受背景干扰等特点,提出一种基于YOLOv8n的焊接缺陷检测算法YOLOSBRS.首先利用空间和通道重建卷积(spatial and channel reconstruction convolution,SCConv)卷积改进主干网络的C2f模块;同时设计一种具有双层路由注意力机制的空间金字塔快速平均池化(spatial pyramid pooling fast average pooling with biformer attention module, SPPF_ABF)模块,将原始SPPF模块的最大池化替换为平均池化操作,并引入双层路由Transformer注意力机制;其次采用重参数化广义特征金字塔网络(reparameterized generalized feature pyramid network,RepGFPN)优化特征融合部分;最后,基于参数共享原理及引入联合空间到深度层和非跨步卷积层模块(a module combining space-to-depth and non-strided convolutional layers,SPD_Conv)改进检测头,实现轻量化的同时提升网络对复杂缺陷的检测能力.试验结果表明,改进后算法的精度和交并比为50%的平均精度均值(mean average precision at 50%intersection over union,mAP50)分别提高3.1%和2.8%,为焊接缺陷检测提供一种高效且可行的解决方案.
