Natural Porous Carbon Derived from Popped Rice as Anode Materials for Lithium-Ion Batteries

Popped rice carbons (PC) were derived from popped rice by using a facile and low-cost technique. PC was then activated by different kinds of activating agents, such as potassium hydroxide (KOH), zinc chloride (ZnCl2), iron (III) chloride (FeCl3), and magnesium (Mg), in order to increase the number of pores and specific surface area. The phase formation of porous activated carbon (PAC) products after the activation process suggested that all samples showed mainly graphitic, amorphous carbon, or nanocrystalline graphitic carbon. Microstructure observations showed the interconnected macropore in all samples. Moreover, additional micropores and mesopores were also found in all PAC products. The PAC, which was activated by KOH (PAC-KOH), possessed the largest surface area and pore volume. This contributed to excellent electrochemical performance, as evidenced by the highest capacity value (383 mAh g−1 for 150 cycles at a current density of 100 mA g−1). In addition, the preparation used in this work was very simple and cost-effective, as compared to the graphite preparation. Experimental results demonstrated that the PAC architectures from natural popped rice, which were activated by an optimal agent, are promising materials for use as anodes in LIBs.