Scalable synthesis of porous silicon nanoparticles from rice husk with the addition of KBr as a scavenger agent during reduction by the magnesiothermic method as anode lithium-ion batteries with sodium alginate as the binder

Abstract

Porous silicon nanoparticle has been synthesized via a highly scalable heat scavenger-assisted magnesiothermic reduction of rice husk. Addition of KBr as scavenger agent for the highly exothermic magnesium reduction process. Porous silicon nanoparticles are a promising anode material for lithium-ion batteries. Effective binders can keep porous silicon nanoparticle anode materials from breaking down and losing their anode capacity because of the massive volume changes during alloy dealloying. The porous silicon nanoparticles are characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), nitrogen adsorption, and scanning electron microscope (SEM). The application of silicon nanoparticles on lithium-ion batteries with sodium alginate as the binders resulted in a good performance. The cyclic voltammetry (CV) curve of PSiNPs-1 shows a reduction peak at 0.17 V with oxidation peaks at 0.77 V. PSiNPs-1.5 shows a reduction peak at 0.18 V with oxidation peaks at 0.83 V. PSiNPs-2 shows a reduction peak at 0.20 V with oxidation peaks at 0.83 V. The PSiNPs-1 after the first cycle shows the charge-transfer resistance (Rct) value of 488 Ω, lower than PSiNPs-1.5 and PSiNPs-2. It indicates an improved charge transferability, confirming the role of porous silicon nanoparticles in enhancing electrical conductivity. Warburg coefficient of PSiNPS-1 shows lower impedance, suggesting the greatly enhanced lithium ions transport inside the active material particles. In comparison, the PSiNPs-1 electrode delivers a high initial specific capacity of 2777 mAh g−1 and maintains a specific capacity of 2579 mAh g−1 after 100 cycles.