Yolk-shell silicon/carbon composite encapsulated by uniform carbon shell (Si@C) are becoming an effective method to mitigate volume-related issues of Si-based anodes and maintain an excellent performance for lithium-ion batteries (LIBs). However, a uniform carbon shell in Si@C is difficult to guarantee. Herein, a facile surface-engineering-assisted strategy is described to prepare Si@C composite with low-cost modified recycled waste silicon powders (RWSi) as core coated by a uniform carbon shell-protective layer derived from the pyrolysis of poly (methyl methacrylate) (PMMA) as carbon source (m-RWSi@PMMA-C). In this process, surface-engineering is performed with silane coupling agent kh550 to functionalize the RWSi particles via a silanization reaction, guaranteeing a uniform PMMA coating which will be transformed into carbon shell-protective layer after carbonization. The m-RWSi@PMMA-C electrode delivers an optimal discharge capacity of 1083 mAhg⁻¹ at 200 mAg⁻¹ after 200 cycles with an initial capacity of 3176.2 mAhg⁻¹ and a high initial Coulombic efficiency (ICE) of 75.6%. Based on these results, the recycled silicon-based anode with a uniform carbon shell-protective layer displays great application potential and it also brings a new perspective on silicon-based anodes via surface-engineering method for LIBs.

通过均匀碳壳（Si @ C）封装的卵黄壳硅/碳复合材料正成为缓解硅基阳极体积相关问题并保持锂离子电池（LIB）优异性能的有效方法。但是，很难保证Si @ C中碳壳的均匀性。本文描述了一种简便的表面工程辅助策略，以低成本改性的再生废硅粉（RWSi）为核，并涂覆有由聚甲基丙烯酸甲酯热解得到的均一的碳壳保护层，制备Si @ C复合材料。 ）（PMMA）作为碳源（m-RWSi @ PMMA-C）。在此过程中，使用硅烷偶联剂kh550进行表面工程处理，以通过硅烷化反应将RWSi颗粒官能化，保证均匀的PMMA涂层，碳化后将转化为碳壳保护层。m-RWSi @ PMMA-C电极可提供1083 mAhg的最佳放电容量^-1在200 MAG ^-1 200个循环，3176.2 mAhg的初始容量之后^-1和75.6％的高的初始库仑效率（ICE）。基于这些结果，具有均匀碳壳保护层的可循环使用的硅基阳极显示出巨大的应用潜力，并且也通过表面工程方法为锂离子电池带来了硅基阳极的新观点。