Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries
Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries
复制标题
DOI：
10.1021/cm902688w
复制
发表时间：
2010-02-09
影响因子：
8.6
通讯作者：
Larcher, D.
中科院分区：
文献类型：
--
作者：
Bridel, J. -S.;Azais, T.;Larcher, D.
制备了各种Si/碳/聚合物复合电极，以更好地了解Si-聚合物相互作用对稳定性或Li-Si反应的影响，特别是尽管Si颗粒在循环过程中体积变化很大，但CMC基（羧甲基纤维素）复合材料的优越性能。通过对复合材料配方、聚合物性质、取代基的性质和数量以及 Si 颗粒的表面化学的修改，以及使用各种表征技术（TEM、SEM、NMR-MAS、红外光谱、TGA 等），我们可以提出 Si/Csp/CMC 复合电极的性能既取决于电极的多孔结构，又取决于 Si-聚合物化学键合的性质。相当强的 Si-CMC 氢键的自修复过程可以适应结构应力并可以在循环过程中演变，这对于硅基电极的性能至关重要。这种更好的理解导致硅基电极的设计，其容量保持率在至少 100 个周期内达到 1000 mAh/g 复合材料（即全硅容量），并且每个周期的库仑效率接近 99.9%。由于这些新方面，我们现在对 CMC 粘合剂的具体效果有了更深入的了解，并且可以成功扩展到其他金属（Sn、Ge、Sb）。
Various Si/carbon/polymer composite electrodes were prepared to better understand the influence of the Si-polymer interactions on the stability or the Li-Si reaction and especially the superior performances of CMC-based (carboxy-methyl-cellulose)composites despite the large volume changes of the Si particles upon cycling. Via the modification of the composites formulation, the nature of the polymer, the nature and the amount of the substituting groups and the surface chemistry of the Si particles, together with the use of various characterization techniques (TEM, SEM, NMR-MAS, infrared spectroscopy, TGA, etc.) we could propose that the performances of the Si/Csp/CMC composite electrodes are nested in both the porous texture of the electrode and in the nature of the Si-polymer chemical bonding. A self-healing process of the rather strong Si-CMC hydrogen bonding which can accommodate textural stresses and can evolve during cycling is proposed to be critical for Si-based electrode performances. This better understanding leads to the design of Si-based electrodes with capacity retention reaching 1000 mAh/g of composite (i.e., full Si capacity) for at least 100 cycles and with a Coulombic efficiency close to 99.9% per cycle. Owing to these new aspects, we have now a deeper insight of the specific effects of the CMC binder, than could be successfully extended to other metals (Sn, Ge, Sb).