铬氧化物正极材料的改性及其应用研究

Modification and application of chromium oxide cathode materials

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%)。

Chromium oxide material(Cr_(8)O_(21))has poor discharge rate performance when used as positive electrode material for lithium primary batteries.Al_(2)O_(3) and TiO_(2) were used to modify Cr_(8)O_(21)by high-temperature solid-phase method,and the rate capability of Cr_(8)O_(21) was improved through the synergistic effect between metal oxides.XRD results showed that coating Al_(2)O_(3) and TiO_(2) does not change the crystal structure of Cr_(8)O_(21);SEM,EDS results showed that Al_(2)O_(3) and TiO_(2) were uniformly coated on the surface of Cr_(8)O_(21).The Cr_(8)O_(21)/Al_(2)O_(3) composite has the best discharge performance with a composite ratio of 50:1,with a capacity of 342 mAh/g(0.05 mA/cm^(2)),291 mAh/g(1.0 mA/cm^(2)),and a capacity retention rate of 85%.The Cr_(8)O_(21)/TiO_(2) composite has the best discharge performance with a composite ratio of 100:1,with a capacity of 362 mAh/g(0.05 mA/cm^(2)),303 mAh/g(1.0 mA/cm^(2)),and a capacity retention rate of 83.75%.There is no voltage drop phenomenon at high current density,and the capacity retention rate is higher than that of Cr_(8)O_(21)(75%).