Abstract:

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.

Key words: lithium ion battery, spray drying, silicon carbon particle, surface sunken