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
SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1~4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10...SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1~4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10-7:1.02×10 7:0.87×107=1.66:1.33:1.1 7:1,浸渍混合饱和溶液的抗氧化能力比浸渍Ca3(PO4)2饱和溶液强.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SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1~4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10-7:1.02×10 7:0.87×107=1.66:1.33:1.1 7:1,浸渍混合饱和溶液的抗氧化能力比浸渍Ca3(PO4)2饱和溶液强.