Lu Zhiyao, Li Bing, Yang Daijun, Lv Hong, Xue Mingzhe, Zhang Cunman
School of Automotive Studies, Tongji University Shanghai 201804 P. R. China
Clean Energy Automotive Engineering Center, Tongji University Shanghai 201804 P. R. China.
RSC Adv. 2018 Jan 17;8(7):3477-3482. doi: 10.1039/c7ra13580g. eCollection 2018 Jan 16.
Silicon, with advantages such as high theoretical capacity and relatively low working potential, has been regarded as promising when it is used for lithium-ion battery anodes. However, its practical application is impeded by the intrinsic low electrical conductivity and the dramatic volume change during the lithiation/delithiation process, which leads to a rapid capacity fading of the electrode. In this regard, we design silicon nanoparticles homogeneously coated with a phenolic resin-based carbon layer as a core-shell nanocomposite a facile self-assembly method followed by carbonization. The surrounding carbon shell, confirmed by transmission electron microscopy and Raman spectroscopy, is not only beneficial to the formation of a stable solid electrolyte interface film, but the electrical conductivity of the electrode is also enhanced. A high and stable specific capacity of nearly 1000 mA h g is achieved at C/3 after 200 cycles with a coulombic efficiency of >99.6%. The entire synthesis process is quite simple and easy to scale up, thus having great potential for commercial applications.
硅由于具有理论容量高和工作电位相对较低等优点，在用作锂离子电池阳极时被认为很有前景。然而，其实际应用受到固有低电导率以及锂化/脱锂过程中巨大体积变化的阻碍，这导致电极容量迅速衰减。在这方面，我们设计了一种均匀包覆有酚醛树脂基碳层的硅纳米颗粒作为核壳纳米复合材料，采用简便的自组装方法随后进行碳化。通过透射电子显微镜和拉曼光谱证实，周围的碳壳不仅有利于形成稳定的固体电解质界面膜，而且还提高了电极的电导率。在200次循环后，以C/3的电流密度可实现近1000 mA h g的高且稳定的比容量，库仑效率>99.6%。整个合成过程非常简单且易于扩大规模，因此具有很大的商业应用潜力。
