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
Lithium-ion battery cathode material Li3V2(PO4)3 was synthesized by sol-gel method using LiOH·H2O, NH4VO3, H3PO4 and citric acid as the raw materials. The samples were investigated by granularity analysis, scanni...Lithium-ion battery cathode material Li3V2(PO4)3 was synthesized by sol-gel method using LiOH·H2O, NH4VO3, H3PO4 and citric acid as the raw materials. The samples were investigated by granularity analysis, scanning electron microscopy and X-ray diffraction. Results showed that sample synthesized by sol-gel procedure had a relatively smaller particle size compared with the products prepared by solid-state reaction, and had an ample surface. Electrochemical properties were investigated by charge/discharge cycle at 0.1 C rate with lithium as the anode. A high discharge specific capacity 122.42 mAh·g-1 was reached at the first cycle, with hardly capacity fading after 20 cycles.展开更多
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.
文摘Lithium-ion battery cathode material Li3V2(PO4)3 was synthesized by sol-gel method using LiOH·H2O, NH4VO3, H3PO4 and citric acid as the raw materials. The samples were investigated by granularity analysis, scanning electron microscopy and X-ray diffraction. Results showed that sample synthesized by sol-gel procedure had a relatively smaller particle size compared with the products prepared by solid-state reaction, and had an ample surface. Electrochemical properties were investigated by charge/discharge cycle at 0.1 C rate with lithium as the anode. A high discharge specific capacity 122.42 mAh·g-1 was reached at the first cycle, with hardly capacity fading after 20 cycles.
