Comparison of the Reactions Between Li x Si or Li0.81C6 and Nonaqueous Solvent or Electrolytes at Elevated Temperature
Comparison of the Reactions Between Li x Si or Li0.81C6 and Nonaqueous Solvent or Electrolytes at Elevated Temperature
复制标题
DOI：
10.1149/1.2354458
复制
发表时间：
2006-12
影响因子：
3.9
通讯作者：
Yadong Wang;J. Dahn
中科院分区：
文献类型：
--
作者：
Yadong Wang;J. Dahn
采用加速量热法，比较了锂化硅（Li x Si）与碳酸乙烯/碳酸二乙酯（EC/DEC）溶剂、lipf6 -或双草酸锂（LiBOB）基电解质在高温下的反应，并与相同溶剂或电解质下的Li 0.81 c6的反应进行了比较。尽管Li x Si的比表面积更大，但Li x Si与所有溶剂或电解质样品反应时的自热速率都小于Li 0.81 c6与相同液体反应时的自热速率。在EC/DEC中加入lipf6或二草酸锂（LiBOB）盐，可以显著抑制Li x Si和Li 0.81 c6样品的自热速率。这项研究表明，在锂离子电池中，至少在初始循环期间，使用硅基粉末电极材料的复合电极应该比相应的石墨电极更安全。同等容量（mAh）的Li x Si比Li 0.81 c6更安全，因为硅每单位体积比石墨可以储存更多的锂，导致反应产物的薄膜更厚，从而减缓与溶剂或电解质的进一步强反应。
The reaction of lithiated silicon (Li x Si) with ethylene carbonate/diethyl carbonate (EC/DEC) solvent, LiPF 6 - or lithium bisoxalatoborate (LiBOB)-based electrolyte at elevated temperature was compared with that of Li 0.81 C 6 and the same solvent or electrolyte using accelerating rate calorimetry. The self-heating rate of Li x Si reacting with all solvent or electrolyte samples was less than that of Li 0.81 C 6 reacting with the same liquids, even though the specific surface area of Li x Si was larger. Additions of the salts, LiPF 6 or lithium bisoxalatoborate (LiBOB), to EC/DEC suppresses the self-heating rate dramatically for both Li x Si and Li 0.81 C 6 samples. This work suggests that composite electrodes using powdered Si-based electrode materials should be safer than corresponding graphite electrodes in Li-ion cells at least during initial cycling. An equal capacity (mAh) of Li x Si is safer than Li 0.81 C 6 because silicon can store more Li per unit volume than graphite, leading to thicker films of reaction products that slow the further strong reaction with solvent or electrolyte.