二氧化硅空心球/碳锂离子电池负极材料

Silica Hollow Sphere/Carbon Lithium-ion Battery Anode Materials

锂离子电池具有能量密度高、使用寿命长、绿色环保、安全性能良好等优点。二氧化硅具有较高的理论比容量、储量丰富、绿色无污染等特点,是最有前景的锂离子电池负极材料之一。但二氧化硅在脱嵌锂过程中产生的体积效应,使得锂离子电池的性能大大降低。为提高锂离子电池的电化学性能,本文制备了二氧化硅/碳(SiO_(2)@C)复合材料,并将其作为锂离子电池负极材料。中空结构有效地缓解了二氧化硅充放电过程中的体积膨胀,提高了复合材料在锂化过程中的结构稳定性。碳层可以作为“缓冲层”,缓解了二氧化硅的体积膨胀,同时碳具有良好的导电性,可以提高复合材料的导电性。在0.1 Ag^(-1)电流密度下经过50次循环后,SiO_(2)@C的放电比容量为766.2 mAhg^(-1),表现出良好的电化学性能。

Lithium-ion batteries have the advantages of high energy density,long service life,green environment protection and good safety performance.Silica is one of the most promising anode materials for lithium-ion batteries because of its high theoretical specific capacity,abundant reserves,and pollution-free characteristics.However,the volume effect of silica in the process of lithiation/delithiation makes the performance of lithium-ion batteries greatly reduced.To improve the electrochemical performance of lithium-ion batteries,silica/carbon(SiO_(2)@C)composites were prepared in this paper and used as anode materials for lithium-ion batteries.The hollow structure effectively alleviates the volume expansion of silica during charging and discharging,and improves the structural stability of composites during lithiation/delithiation process.The carbon layer can be used as a buffer layer to mitigate the volume expansion of silica,and carbon has good electrical conductivity,which can improve the electrical conductivity of composites.After 50 cycles at 0.1 Ag^(-1) current density,the discharge capacity of SiO_(2)@C is 766.2 mAhg^(-1),which exhibits good electrochemical performance.