SiO2/C Composite as a High Capacity Anode Material of LiNi0.8Co0.15Al0.05O2 Battery Derived from Coal Combustion Fly Ash

Abstract

Abundantly available SiO2 (silica) has great potential as an anode material for lithium-ion batteries because it is inexpensive and flexible. However, silicon oxide-based anode material preparation usually requires many complex steps. In this article, we report a facile method for preparing a SiO2/C composite derived from coal combustion fly ash as an anode material for Li-ion batteries. SiO2 was obtained by caustic extraction and HCl precipitation. Then, the SiO2/C composite was successfully obtained by mechanical milling followed by heat treatment. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Electrochemical properties were tested using an 18650 cylindrical cell utilizing LiNi0.8Co0.15Al0.05O2 (NCA) as the counter electrode. Based on the obtained results, the physiochemical characteristics and electrochemical performance, it was determined that SiO2/C composites were greatly affected by the temperature of heat treatment. The best result was obtained with the SiO2 content of 10% w/w, heating temperature of 500 °C, initial specific discharge capacity of 586 mAh g−1 at 0.1 C (1 C = 378 mAh g−1), and reversible capacity of 87% after 20 cycles. These results confirmed that the obtained materials had good initial discharge capacity, cyclability, high performance, and exhibited great potential as an anode material for LIBs.

A Review: The Development of SiO2/C Anode Materials for Lithium-Ion Batteries

“…Jumari et al 22 reported a similar result, where the increase in SiO 2 content in SiO 2 /C resulted in a high specific capacity. However, the initial CE tended to decrease.…”

“…Recently, waste or industrial side products have been widely used as a source of SiO 2 . For example, Jumari et al 22 synthesized SiO 2 /C using fly ash combustion as a source of SiO 2 , Wu et al 50 used electronic waste, and Widiyandari et al 23 used geothermal sludge for the synthesis of SiO 2 /Mg. The use of waste or industrial side products potentially reduces the production cost of lithiumion batteries and can overcome environmental problems.…”

“…20 The porous structure can also increase the reversible capacity of lithium-ion batteries owing to the presence of many active networks. 16,65 Yan et al 22 synthesized hollow porous SiO 2 nanocubes with a high reversible capacity of 919 mAh g −1 after 30 cycles. The porous structure accelerates the transport of lithium ions, so that the formation of Li 2 and Si takes place quickly.…”

“…13 Si is the most promising alternative anode material among Si-based materials due to its highest theoretical capacity (4200 mAh g −1 ). 12,14 However, the extreme volume changes during the lithiation/delithiation process, due to the formation of the Li-S alloy (Li 22 Si 5 , up to 300%), becomes the main problem of Si. 11,12 Therefore, SiO 2 has become an alternative to Si due to its expansion volume, which is the lowest (100%) compared to Si (300%) and SiO (150%).…”

“…15,16 However, the low initial coulombic efficiency (52.38%) and electrical conductivity due to strong Si-O bonds are significant obstacles to the development of SiO 2 as an anode material. 15,[17][18][19] Several studies have been developed, such as the use of the amorphous phase of SiO 2 , 17 nanostructure modification of SiO 2 , 20 modification of SiO 2 particle size, 21 modification of SiO 2 composition, 22 and modification of the synthesis method, 23 which aim to improve the electrochemical performance of SiO 2 . However, recent studies have focused on adding an agent that can increase the conductivity of SiO 2 , such as carbon materials, which effectively enhances the electrochemical performance of SiO 2 .…”