预歧化处理的高性能锂离子电池SiO/C负极材料

以SiO和蔗糖为原料,SiO经高温歧化反应处理后,通过机械球磨、喷雾干燥、高温热解工艺制备出具有优异电化学性能的锂离子电池SiO/C负极材料。经XRD、FTIR、XPS、SEM、TEM结构分析表明,歧化反应处理的片状SiO包含非晶态SiO和纳米晶相Si、SiO_2,蔗糖热解形成的无定形碳包覆在细片状SiO的表面,组成球形SiO/C颗粒。电化学测试结果表明,预歧化处理的SiO/C复合材料的首次放电容量为1 314.6mAh/g,首次库伦效率达到71%;100周循环后的放电容量为851.2mAh/g,容量保持率达到78.5%,循环稳定性远高于未经歧化处理的SiO/C复合材料。电化学性能的提高归因于SiO预歧化反应及热解碳包覆。

High-performance SiO/C Anode Material in Li-ion Battery by Pre-disproportionation Treatment

Starting from the SiO and sucrose, a SiO/C composite for Li-ion battery anode material with excellent electrochemical performance was prepared by the disproportionation treatment of SiO at high temperature, which was followed by mechanical milling, spray drying and pyrolysis. XRD, FTIR, XPS, SEM, TEM analysis indicated that there exist amorphous SiO, crystalline Si and SiO₂ in the disproportionated SiO plates, and the prepared spherical SiO/C particles were composed of refined SiO plates, which were coated with pyrolyzed disordered carbon. The pre-disproportionated SiO/C composite exhibited an initial discharge capacity of 1 314.6 mAh/g with an initial Coulombic efficiency of 71% at 100 mA/g, and a discharge capacity of 851.2 mAh/g after 100 cycles. The capacity retention of disproportionated SiO/C composite was 78.5%, which was much higher than that for undisproportionated SiO/C composite. The excellent electrochemical performances are attributed to the disproportionation of SiO and the pyrolytic carbon coating.