Exploring silicon nanoparticles and nanographite-based anodes for lithium-ion batteries

Abstract

AbstractThis study investigates the performance of silicon nanoparticles (Si NPs) and silicon nanographite (SiNG) composite-based anodes for lithium-ion batteries (LiBs). Si offers a promising alternative to traditional graphite anodes due to its higher theoretical capacity, despite encountering challenges such as volume expansion, pulverization, and the formation of a solid electrolyte interface (SEI) during lithiation. SiNPs anode exhibited initial specific capacities of 1568.9 mAh/g, decreasing to 1137.6 mAh/g after 100th cycles, with stable Li–Si alloy phases and high Coulombic efficiency (100.48%). It also showed good rate capability, retaining 1191.3 mAh/g at 8400 mA g−1 (2.82C), attributed to its carbon matrix structure. EIS indicated charge transfer with RB of 3.9 Ω/cm−2 and RCT of 11.4 Ω/cm−2. Contrastingly, SiNG composite anode had an initial capacity of 1780.7 mAh/g, decreasing to 1297.5 mAh/g after 100 cycles. Its composite structure provided cycling stability, with relatively stable capacities after 50 cycles. It exhibited good rate capability (1191.3 mAh/g at 8399.9 mA g−1), attributed to its carbon matrix structure. Electrochemical impedance spectroscopy showed higher resistances for RB of 4.2 Ω/cm−2 and RCT of 15.6 Ω/cm−2 compared to SiNPs anode. These findings suggest avenues for improving energy storage devices by selecting and designing suitable anode materials.