Adjusting ash content of char to enhance lithium storage performance of rice husk-based SiO2/C

Rice husk-based SiO2/C composite is a promising anode material for lithium ion battery, but it remains necessary to explore simple methods to improve its lithium storage performance. In this research, SiO2/C was prepared by adjusting ash content of pyrolyzed rice husk (PRH) using NaOH solution to study the effects of ash content adjustment on lithium storage performance of SiO2/C. The adjustment significantly affected the pore structure and lithium storage performance of the SiO2/C composite. The SiO2/C with ash content of 19.2 wt% ash exhibited a superior reversible capacity of 886 mA h/g at 200 mA/g, which ranked among the highest values ever reported for SiO2/C composites; this sample also showed excellent cyclic stability and good rate performance (381 mA h/g at 2000 mA/g). The good electrochemical performance was mainly due to the abundant pores (particularly mesopores) in the composite and to the synergistic effect between carbon and SiO2. Adjusting ash content of char was an effective method for enhancing lithium storage performance of SiO2/C. (C) 2020 Elsevier B.V. All rights reserved.