铬氧化物材料(Cr8O21)用作锂一次电池正极材料时放电倍率性能较差。利用高温固相法以Al_(2)O_(3)、TiO_(2)对Cr8O_(21)进行包覆改性,通过金属氧化物间的协同作用提升了Cr_(8)O_(21)的倍率性能。X射线衍射(XRD)结果显示包覆Al_(2)O_(3)、...铬氧化物材料(Cr8O21)用作锂一次电池正极材料时放电倍率性能较差。利用高温固相法以Al_(2)O_(3)、TiO_(2)对Cr8O_(21)进行包覆改性,通过金属氧化物间的协同作用提升了Cr_(8)O_(21)的倍率性能。X射线衍射(XRD)结果显示包覆Al_(2)O_(3)、TiO_(2)不会改变Cr_(8)O_(21)的晶体结构;扫描电子显微镜(SEM)、能量散射光谱(EDS)结果表明Al2O3和Ti O2都均匀包覆在Cr_(8)O_(21)表面。Cr_(8)O_(21)/Al_(2)O_(3)复合材料以质量比50∶1复合时放电性能最佳,比容量为342 m Ah/g (0.05 m A/cm^(2))、291 m Ah/g(1.0 m A/cm^(2)),容量保持率85%;Cr_(8)O_(21)/TiO_(2)复合材料以质量比100∶1复合时放电性能最佳,比容量为362 m Ah/g(0.05 m A/cm^(2))、303 m Ah/g (1.0 m A/cm^(2)),容量保持率83.75%。在大电流密度下无电压低头现象,容量保持率皆高于Cr8O21的容量保持率(75%)。展开更多
Cathode materials,nickel doped Cr_(8)O_(21),were synthesized by a solid-state method.The effects of Ni doping on the electrochemical performances of Cr_(8)O_(21) were investigated.The experimental results show that th...Cathode materials,nickel doped Cr_(8)O_(21),were synthesized by a solid-state method.The effects of Ni doping on the electrochemical performances of Cr_(8)O_(21) were investigated.The experimental results show that the discharge capacities of the samples depend on the nickel contents,which increases firstly and then decreases with increasing Ni contents.Optimized Ni_(0.5)Cr_(7.5)O_(21)delivers a first capacity up to 392.6 m Ah·g^(-1)at 0.1C.In addition,Ni doped sample also demonstrates enhanced cycling stability and rate capability compared with that of the bare Cr_(8)O_(21).At 1 C,an initial discharge capacity of 348.7 m Ah·g^(-1)was achieved for Ni_(0.5)Cr_(7.5)O_(21),much higher than 271.4 m Ah·g^(-1)of the un-doped sample,with an increase of more than 28%.Electrochemical impedance spectroscopy results confirm that Ni doping reduces the growth of interface resistance and charge transfer resistance,which is conducive to the electrochemical kinetic behaviors during charge-discharge.展开更多
文摘铬氧化物材料(Cr8O21)用作锂一次电池正极材料时放电倍率性能较差。利用高温固相法以Al_(2)O_(3)、TiO_(2)对Cr8O_(21)进行包覆改性,通过金属氧化物间的协同作用提升了Cr_(8)O_(21)的倍率性能。X射线衍射(XRD)结果显示包覆Al_(2)O_(3)、TiO_(2)不会改变Cr_(8)O_(21)的晶体结构;扫描电子显微镜(SEM)、能量散射光谱(EDS)结果表明Al2O3和Ti O2都均匀包覆在Cr_(8)O_(21)表面。Cr_(8)O_(21)/Al_(2)O_(3)复合材料以质量比50∶1复合时放电性能最佳,比容量为342 m Ah/g (0.05 m A/cm^(2))、291 m Ah/g(1.0 m A/cm^(2)),容量保持率85%;Cr_(8)O_(21)/TiO_(2)复合材料以质量比100∶1复合时放电性能最佳,比容量为362 m Ah/g(0.05 m A/cm^(2))、303 m Ah/g (1.0 m A/cm^(2)),容量保持率83.75%。在大电流密度下无电压低头现象,容量保持率皆高于Cr8O21的容量保持率(75%)。
基金National Natural Science Foundation of China(No.51790490)。
文摘Cathode materials,nickel doped Cr_(8)O_(21),were synthesized by a solid-state method.The effects of Ni doping on the electrochemical performances of Cr_(8)O_(21) were investigated.The experimental results show that the discharge capacities of the samples depend on the nickel contents,which increases firstly and then decreases with increasing Ni contents.Optimized Ni_(0.5)Cr_(7.5)O_(21)delivers a first capacity up to 392.6 m Ah·g^(-1)at 0.1C.In addition,Ni doped sample also demonstrates enhanced cycling stability and rate capability compared with that of the bare Cr_(8)O_(21).At 1 C,an initial discharge capacity of 348.7 m Ah·g^(-1)was achieved for Ni_(0.5)Cr_(7.5)O_(21),much higher than 271.4 m Ah·g^(-1)of the un-doped sample,with an increase of more than 28%.Electrochemical impedance spectroscopy results confirm that Ni doping reduces the growth of interface resistance and charge transfer resistance,which is conducive to the electrochemical kinetic behaviors during charge-discharge.
