Lithium exchange mechanism, local structure, and its possible evolutions on lithium ion extraction and reinsertion are studied in Si-O-C materials. As the silicon distributions and microstructure change with the synthetic method, the relationship between the capacity and silicon structures is evaluated. By comparing derivative capacity curves of the ordinary anode materials composed of Si, C, or O, silicon species in terms of SiO_nC_4-n (1 ≤ n ≤ 4) are deduced to be the main source of lithium storage in Si-O-C materials. Of all the silicon species, SiO_nC_4-n (2 ≤ n ≤ 4) are confirmed to be reversible with lithium, but SiOC₃ species be irreversible, by tracing the silicon structural changes during lithium insertion/distraction utilizing ²⁹Si MAS NMR. Galvanostatic tests show the reversible capacity increases with the increase of the sum of SiO_nC_4-n (2 ≤ n ≤ 4) and decreases with the increase of SiOC₃ content. Furthermore, a model is established to express the relationship between the capacity and silicon species. According to the model, 1 mol of SiO₄, SiO₃C, SiO₂C₂, or SiOC₃ species can reversible deliver 3.0, 2.5, 0.5, or 0 mol of lithium ions, respectively. Applied to the reported data, the predictive capacities following the model agree well with the experimental values.

中文翻译：

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Si-OC材料中硅物种中锂的存储研究

研究了Si-OC材料中的锂交换机理，局部结构及其在锂离子萃取和重新插入过程中的可能演化。随着合成方法中硅分布和微观结构的变化，评估了容量与硅结构之间的关系。通过以SiO方面进行比较的Si，C或O构成的普通的阳极材料，硅物种的衍生物容量曲线_Ñ Ç _{4- Ñ}（1≤  Ñ  ≤4）推导为锂存储在SI-主要来源超频材料。所有的硅物种，二氧化硅的_Ñ Ç _{4- Ñ}（2≤  Ñ  ≤4）被确认为是可逆的锂，但的SiOC ₃通过使用²⁹ Si MAS NMR追踪锂插入/分散过程中的硅结构变化，这些物种是不可逆的。恒电流测试显示与二氧化硅的总和的增加而可逆容量增大_Ñ Ç _{4- Ñ}（2≤  Ñ  ≤4）并用的SiOC的增加而减小₃的内容。此外，建立了一个模型来表达容量和硅种类之间的关系。根据该模型，SiO ₂，SiO ₃ C，SiO ₂ C ₂或SiOC _3为1 mol物种可以可逆地分别输送3.0、2.5、0.5或0摩尔的锂离子。应用于报告的数据，模型的预测能力与实验值非常吻合。