Quratul Aini, Pilar Bela Persada, M. Hamzah Raihan Pasha, Naufal Hanif Hawari, Afriyanti Sumboja
Silicon oxide (SiOx) is a promising Si-based anode due to its abundant natural resources and high theoretical capacity. Beyond the Earth’s crust, extracting SiOx from phytolith-rich plants offers a sustainable alternative, where the organic carbon can naturally occlude within the phytolith structure. This work examines the phytolith characteristics and the anode performance of the resultant SiOx/carbon composite (SiOx/C) derived from wild grass phytolith-rich plants (i.e., Goosegrass and Ghaeri’s Rush). While Ghaeri’s Rush phytoliths exhibit cavate morphology with occluded carbon located within thin silica walls and cavities, Goosegrass solid phytoliths feature a dense solid silica matrix with occluded carbon tightly isolated throughout the solid silica matrix. This characteristic leads to superior characteristics for SiOx/C anodes derived from Goosegrass, which exhibit a larger amount of active SiOx, wider surface area (1408 m2 g-1), and a higher amount of defective carbon, compared to those derived from Ghaeri’s Rush. In addition, X-ray photoelectron spectroscopy shows that the Si content in SiOx/C derived from Goosegrass mostly consists of active SiOx with a low organosilicon content (12.96%). These characteristics of Goosegrass improve the SiOx/C anode’s gravimetric capacity, cycling durability, and capability of the charge-discharge rate, delivering 704 mAh g-1 after 500 charge-discharge cycles at 200 mA g-1 without any capacity degradation. It also achieves a capacity as high as 330 mAh g-1 during a rate capability test at 1000 mA g-1. This study highlights the potential of phytolith-rich wild grasses for sustainable and stable Li-ion battery technology by emphasizing the influence of phytolith characteristics on the SiOx/C anode properties. © 2024 American Chemical Society.
Department of Materials Engineering, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, Lampung Selatan, 35365, Indonesia; Material Science and Engineering Research Group, Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia; School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore