Cong Ruye, Park Hyun-Ho, Jo Minsang, Lee Hochun, Lee Chang-Seop
Department of Chemistry, Keimyung University, Daegu 42601, Korea.
Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
Molecules. 2021 Aug 10;26(16):4831. doi: 10.3390/molecules26164831.
Silicon-carbon nanocomposite materials are widely adopted in the anode of lithium-ion batteries (LIB). However, the lithium ion (Li) transportation is hampered due to the significant accumulation of silicon nanoparticles (Si) and the change in their volume, which leads to decreased battery performance. In an attempt to optimize the electrode structure, we report on a self-assembly synthesis of silicon nanoparticles@nitrogen-doped reduced graphene oxide/carbon nanofiber (Si@N-doped rGO/CNF) composites as potential high-performance anodes for LIB through electrostatic attraction. A large number of vacancies or defects on the graphite plane are generated by N atoms, thus providing transmission channels for Li and improving the conductivity of the electrode. CNF can maintain the stability of the electrode structure and prevent Si from falling off the electrode. The three-dimensional composite structure of Si, N-doped rGO, and CNF can effectively buffer the volume changes of Si, form a stable solid electrolyte interface (SEI), and shorten the transmission distance of Li and the electrons, while also providing high conductivity and mechanical stability to the electrode. The Si@N-doped rGO/CNF electrode outperforms the Si@N-doped rGO and Si/rGO/CNF electrodes in cycle performance and rate capability, with a reversible specific capacity reaching 1276.8 mAh/g after 100 cycles and a Coulomb efficiency of 99%.
硅碳纳米复合材料被广泛应用于锂离子电池（LIB）的负极。然而，由于硅纳米颗粒（Si）的大量聚集及其体积变化，锂离子（Li）的传输受到阻碍，这导致电池性能下降。为了优化电极结构，我们报道了一种通过静电吸引自组装合成硅纳米颗粒@氮掺杂还原氧化石墨烯/碳纳米纤维（Si@N-doped rGO/CNF）复合材料作为LIB潜在高性能负极的方法。N原子在石墨平面上产生大量空位或缺陷，从而为Li提供传输通道并提高电极的导电性。CNF可以维持电极结构的稳定性并防止Si从电极上脱落。Si、N掺杂rGO和CNF的三维复合结构可以有效缓冲Si的体积变化，形成稳定的固体电解质界面（SEI），并缩短Li和电子的传输距离，同时还为电极提供高导电性和机械稳定性。Si@N-doped rGO/CNF电极在循环性能和倍率性能方面优于Si@N-doped rGO和Si/rGO/CNF电极，在100次循环后可逆比容量达到1276.8 mAh/g，库仑效率为99%。
