不同碳含量对SiO/C负极电化学性能的影响

Influence of different carbon contents on the electrochemical performance of SiO/C anode

合理的碳包覆层对SiO负极材料性能的提升至关重要,但是有关碳含量与电极电化学性能之间的内在联系尚未有深入的研究。本工作利用化学气相沉积(CVD)技术制备了不同碳含量的SiO/C负极材料,深入研究发现当碳含量(质量分数)为5%左右时,复合材料的电化学性能表现最优,这归因于该碳含量下材料的锂离子传输效率相对较高;进一步研究发现,当CVD过程的碳含量继续增加时,沉积碳的无序结构占比较大,虽然导电性有所提升,但是原本供锂离子传输的空隙被大量堵塞,极大影响了电极反应动力学。所制备的SiO/C-2电极表现出最优异的循环性能,在经历100个循环后仍然具有1350 mAh/g的可逆容量。

Carbon coating is essential for the performance of SiO anode materials;however,the intrinsic link between carbon content and electrode electrochemical performance has not been studied in depth.Herein,SiO/C anode materials with different carbon contents were prepared using chemical vapor deposition(CVD)technology.The study found that when the carbon content was about 5%,the electrochemical performance of the composite materials was the best because they had a fast lithium-ion transport channel.Further research found that when the carbon content of the CVD process continued to increase,carbon materials with disordered structures accounted for a large proportion.Although the electrical conductivity was improved,the gaps originally available for lithium-ion transport were heavily blocked,which greatly affected the kinetic reaction rate of the electrode.The prepared SiO/C-2 electrode showed excellent cycling performance,with a reversible capacity of 1350 mAh/g after 100 cycles.