Li Xin-Tao, Xiong Qing-Chen, Du Fei-Hu
School of Environmental and Chemical Engineering, Shanghai, University, 99 Shangda Road, Shanghai 200444, P.R. China.
Nanoscale. 2025 Sep 11;17(35):20390-20399. doi: 10.1039/d5nr02198g.
Silicon has the highest theoretical lithium storage capacity, low discharge potential, abundance in the Earth's crust and environment-friendly nature, and has been considered as one of the most promising anode materials for lithium-ion batteries. However, high-cost raw materials, complicated processes and harsh reaction conditions are generally used in the preparation of silicon. In addition, the poor intrinsic conductivity, slow diffusion kinetics of lithium ions and large volume expansion in silicon hinder its further application. Here, Si nanowires@nitrogen-doped hollow carbon spheres (Si NWs@N-HCSs) as anode materials for lithium-ion batteries are prepared by the polystyrene template method, with sodium citrate as the reducing agent, high-temperature carbonization of polypyrrole, and the "supercritical fluid-liquid-solid (SFLS)" growth mechanism. The initial coulombic efficiency of the as-obtained Si NWs@N-HCSs is 72% at a current density of 0.5 A g, and it gives a reversible specific capacity of 568 mAh g after 200 cycles and outstanding rate performance (2709, 2359, 1839, 1566, 1421, and 1028 mAh g at 0.2, 0.5, 1, 2, 4, and 8 A g). The excellent electrochemical behavior of the composite electrode is attributed to the nitrogen-doped carbon spheres with a hollow structure, gold nanoparticles with high conductivity, and silicon with a nanowire structure. This study not only provides a new synthetic idea for the application of silicon in other fields, but also offers a new design strategy for the improvement of the lithium storage properties of silicon-based anode materials.
硅具有最高的理论锂存储容量、低放电电位、在地壳中储量丰富且性质环保，因此被认为是锂离子电池最有前景的负极材料之一。然而，硅的制备通常使用高成本的原材料、复杂的工艺和苛刻的反应条件。此外，硅的本征电导率差、锂离子扩散动力学缓慢以及体积膨胀大，阻碍了其进一步应用。在此，通过聚苯乙烯模板法，以柠檬酸钠为还原剂，对聚吡咯进行高温碳化，并基于“超临界流体-液-固（SFLS）”生长机制，制备了作为锂离子电池负极材料的硅纳米线@氮掺杂空心碳球（Si NWs@N-HCSs）。所制备的Si NWs@N-HCSs在电流密度为0.5 A g时的首次库仑效率为72%，在200次循环后可逆比容量为568 mAh g，并且具有出色的倍率性能（在0.2、0.5、1、2、4和8 A g时分别为2709、2359、1839、1566、1421和1028 mAh g）。复合电极优异的电化学行为归因于具有空心结构的氮掺杂碳球、高电导率的金纳米颗粒以及具有纳米线结构的硅。本研究不仅为硅在其他领域的应用提供了一种新的合成思路，也为改善硅基负极材料的锂存储性能提供了一种新的设计策略。
