With the reform of experimental teaching in colleges and universities,the teaching mode of"experimental students as the main body,experimental teachers as the guide"needs to constantly explore new experiment...With the reform of experimental teaching in colleges and universities,the teaching mode of"experimental students as the main body,experimental teachers as the guide"needs to constantly explore new experimental teaching methods.In this paper,knowledge graph is integrated into the experiment of mechanical principle to guide undergraduates to use knowledge graph to analyze and summarize independently in experimental teaching activities,aiming at cultivating undergraduates interest in learning and innovative thinking,so as to improve the quality of experimental teaching.This study has a certain reference significance for experimental teaching in colleges and universities.展开更多
Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation...Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation during sodium ion de-intercalation and the main frame mechanism remains unchanged,and thus is seen as an energy storage material for a wide range of applications,but has a limited electronic conductivity due to its structure.In this paper,NVP cathode materials with finer primary particles are successfully prepared using a simple hydrothermal treatment-assisted sol-gel method.The increased pore size of the NVP materials prepared under the hydrothermal process allows for more active sites and more effective resistance to the volume deformation of sodium ions during insertion/extraction processes,effectively facilitating the diffusion of ions and electrons.The Na_(3)V_(2)(PO_(4))_(3) material obtained by the optimized process exhibited good crystallinity in XRD characterization,as well as superior electrochemical properties in a series of electrochemical tests.A specific capacitance of 106.3 mAh g^(-1) at 0.2 C is demonstrated,compared to 96.5 mAh g^(-1) for Na_(3)V_(2)(PO_(4))_(3) without hydrothermal treatment,and cycling performance is also improved with 93%capacity retention.The calculated sodium ion diffusion coefficient(DNa=5.68×10^(-14))obtained after EIS curve fitting of the improved sample illustrates that the pore structure is beneficial to the performance of the Na_(3)V_(2)(PO_(4))_(3)cathode material.展开更多
基金Supported by Undergraduate Teaching Research and Reform Project of University of Shanghai for Science and Technology in 2024(JGXM24281&JGXM24263)First-class Undergraduate Course Construction Project of University of Shanghai for Science and Technology in 2024(YLKC202424394).
文摘With the reform of experimental teaching in colleges and universities,the teaching mode of"experimental students as the main body,experimental teachers as the guide"needs to constantly explore new experimental teaching methods.In this paper,knowledge graph is integrated into the experiment of mechanical principle to guide undergraduates to use knowledge graph to analyze and summarize independently in experimental teaching activities,aiming at cultivating undergraduates interest in learning and innovative thinking,so as to improve the quality of experimental teaching.This study has a certain reference significance for experimental teaching in colleges and universities.
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation during sodium ion de-intercalation and the main frame mechanism remains unchanged,and thus is seen as an energy storage material for a wide range of applications,but has a limited electronic conductivity due to its structure.In this paper,NVP cathode materials with finer primary particles are successfully prepared using a simple hydrothermal treatment-assisted sol-gel method.The increased pore size of the NVP materials prepared under the hydrothermal process allows for more active sites and more effective resistance to the volume deformation of sodium ions during insertion/extraction processes,effectively facilitating the diffusion of ions and electrons.The Na_(3)V_(2)(PO_(4))_(3) material obtained by the optimized process exhibited good crystallinity in XRD characterization,as well as superior electrochemical properties in a series of electrochemical tests.A specific capacitance of 106.3 mAh g^(-1) at 0.2 C is demonstrated,compared to 96.5 mAh g^(-1) for Na_(3)V_(2)(PO_(4))_(3) without hydrothermal treatment,and cycling performance is also improved with 93%capacity retention.The calculated sodium ion diffusion coefficient(DNa=5.68×10^(-14))obtained after EIS curve fitting of the improved sample illustrates that the pore structure is beneficial to the performance of the Na_(3)V_(2)(PO_(4))_(3)cathode material.
