构造凹陷的硅碳颗粒提高锂离子电池负极电化学性能

Dented surface on silica-carbon particles to improve the electrochemical performance of lithium-ion battery anode

调控硅碳颗粒的表面形貌和孔隙结构,可以进一步优化锂离子电池负极性能,对开发下一代高比能锂离子动力电池具有重要意义。本工作以光伏工业硅废料为硅源,壳聚糖和酚醛树脂为碳源,以及氯化钙为形貌调控剂,采用喷雾干燥、液相包裹和低温热解法构造了表面凹陷的硅碳颗粒。利用热重分析仪(TGA)、扫描电子显微技术(SEM)和电化学技术等表征测试手段,对比分析了颗粒凹陷程度对负极电化学性能的影响。结果表明,具有较大孔容和表面凹陷结构的非球形颗粒制备的电极中,颗粒间隙小、接触面积大、导电添加剂填充充分,因此电极具有良好的导电能力和离子传输能力,有利于电池循环稳定性。表面凹陷颗粒制备的负极循环400圈后放电比容量保持在680 mAh/g左右。电极的倍率测试结果表明,当电流密度从0.1 C恢复到1 C时,表面凹陷颗粒电极的放电比容量最高恢复率达到了97.8%,充放电性能稳定有助于推动高振实密度硅基锂离子电池负极的应用。

Regulation of the surface morphology and pore structure of silicon carbon particles holds substantial potential for enhancing the performance of lithium-ion battery anodes,which is a crucial advancement for next-generation high-ratio lithium-ion power batteries.In this study,silica-carbon particles with dented surfaces were fabricated using a process involving spray-drying,liquid-phase encapsulation,and low-temperature pyrolysis.Photovoltaic industrial silicon waste served as the silicon source,whereas chitosan and phenol-formaldehyde resin provided the carbon source,with calcium chloride acting as the morphology modifier.By employing thermogravimetric analysis(TGA),scanning electron microscopy(SEM),and electrochemical measurements,we investigated the impact of surface denting on the electrochemical performance of the negative electrode.Our findings indicate that electrodes prepared from nonspherical particles with large pore volumes and dented surfaces exhibit enhanced conductivity and ion transport capabilities owing to the small particle gaps,increased contact area,and adequate filling of conductive additives.These characteristics improve the capacity performance.Specifically,the discharge-specific capacity of the anode prepared from surface-dented particles remained at approximately 680 mAh/g after 400 cycles,with a capacity recovery of 97.8%when the current density reverted from 0.1 C to 1 C.These results underscore the stable charging and discharging performance of the anode,which bodes well for advancing the application of silicon-based lithium-ion batteries in environments with high vibration density.