Facile synthesis of nano-Si/graphite composites from rice husk for high performance lithium-ion battery anodes

Abstract

The hydrothermal method is used to attach nano-Si to the surface of natural graphite to make a high-performance nano-si/graphite (nSi/G) composite. The nSi/G composites have been successfully made from rice husk using the hydrothermal method. The characterizations used XRD, XPS, SEM, TEM, and electrochemical measurements. The results of XRD showed that nano-Si shows 2θ at 28°, 47°, 56°, 69°, and 76° is the diffraction pattern of silica and carbon, respectively. XPS spectrum at nano-Si showed a spectrum at a binding energy of 97.6 eV and 101.2 eV, indicating Si–Si and Si–OH. SEM images on nano-Si show a spherical shape; graphite contains flakes, whereas nano-Si includes every flake on the graphite. The TEM images of the nano-Si particles were around 30–50 nm in diameter and aggregated due to the high surface energy. This composite is used in lithium-ion batteries. This component structure is good for improving the ability to store Li+ because the amorphous graphite layer surrounding the nano-Si has good electric conductivity and strong elasticity to help relax the strain caused by the electrochemical reaction of the Si during cycles. The specific capacity of the nSi/G composite is 3219 mAhg−1, and after 200 cycles, it still has 98.36 % of its initial capacity. The electrochemical results indicate that Si–graphite composites derived from rice husks are viable candidates for high-capacity lithium-ion battery anodes, offering significant battery performance and scalability advantages.

Keywords

• Electrochemical
• Hydrothermal
• Lithium-ion battery
• Silicon anode