SnO_2纳米片容量异常行为的新解释

An explanation to super high capacity of SnO_2 nanosheet anode

纳米SnO_2作为锂离子电池负极材料,充放电容量有时会超过其容量的理论值。传统的解释一般包含以下三个方面:(1)在嵌锂过程中,SnO_2负极材料表面形成的SEI膜消耗或释放部分锂离子;(2)充放电过程中Li2O发生部分可逆反应;(3)纳米材料本身独特的孔结构可储存额外的锂离子。这里,基于所制备的SnO_2纳米片,提出了另外一种可能引起其高容量的原因:即SnO_2本身存在的氧缺陷。通过对SnO_2纳米片在空气以及氮气气氛中的热重分析证实了这一观点。由于液相法制备的SnO_2纳米材料普遍存在氧缺陷,所以氧缺陷可视为引起液相法制备的纳米SnO_2负极材料容量异常行为的另外一种原因。

When used as anode materials for Li-ion batteries, nanostructured SnO2 usually exhibits higher capacity than the theoretical value. The traditional explanations mainly include the SEI film reacts with Li, the partially reversible of Li2O and the meso/hollow structure storage of Li. Via preparation of SnO2 nanosheets accompanying with TG analysis, it is demonstrated that oxygen vacancies of SnO2 anode could be a new reason responsible for the ultra high capacity.