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以高活性、低熔点金属锂为还原剂,在惰性气氛保护下分别将一氧化硅和氧化亚锡还原为单质硅和锡。通过调节球磨参数并加入适量助磨剂有效抑制因金属锂熔化导致的物料结块现象,得到将纳米硅、锡颗粒均匀分散在含锂化合物基体中的二元储锂母体复合材料。通过该方法得到的复合材料中硅、锡颗粒粒径明显小于商品化的纳米硅和纳米锡,不仅能最大限度降低硅、锡颗粒的体积效应,避免纳米粉体的分散工序,且能大大降低材料的制备成本。交流阻抗和充放电循环测试显示,金属锡作为另一种储锂母体既能为复合材料提供部分可逆容量,也能有效降低活性物质颗粒之间的电荷转移电阻,改善材料的循环稳定性。复合材料经过30次循环后仍能释放出高达550mAh·g-1的可逆容量,容量保持率为84%。
With high activity, low melting point metal lithium as reductant, under the protection of an inert atmosphere of silicon monoxide and stannous oxide were reduced to elemental silicon and tin. By adjusting the ball milling parameters and adding proper amount of grinding aid, the material caking phenomenon caused by the metal lithium melting can be effectively suppressed to obtain a binary lithium-storage matrix composite material in which nano-silicon and tin particles are uniformly dispersed in the lithium-containing compound matrix. The particle size of the silicon and tin particles in the composite material obtained by the method is obviously smaller than that of commercialized nano-silicon and nano-tin, and can not only minimize the volume effect of silicon and tin particles but also disperse the nano-powder and greatly reduce Material preparation costs. AC impedance and charge-discharge cycling tests show that metallic tin, as another kind of lithium-storage matrix, can not only provide partial reversible capacity for composite materials, but also effectively reduce the charge transfer resistance between the active material particles and improve the cycle stability of the material. After 30 cycles, the composite can still release reversible capacity of up to 550mAh · g-1 with a capacity retention of 84%.