Silicon oxide (SiOx) is a widely researched Si-based anode due to its simplicity in synthesis, cost-effectiveness, and high theoretical capacity (2680 mAh g–1). However, its poor electrical conductivity and up to 200% volume expansion are significant obstacles to its practical application. Herein, a porous carbon-rich SiOx/C anode was derived from the sole source of para grass using one-step calcination. Para grass offers a sustainable option for biomass, with its considerable lignocellulose and silica compounds that can be used as a renewable precursor. The synthesized SiOx/C shows a high carbon content of ∼89.51 wt % and a mesoporous structure with a surface area of ∼1235 m2 g–1. The high carbon content provides a conductive network, while the porous structure enhances mechanical durability during cycling and provides more sites for lithium-ion insertion/extraction. In a half-cell configuration, the SiOx/C demonstrates a specific capacity of 716 and 299 mAh g–1 at 200 and 1000 mA g–1, respectively. Full-cell configuration of Li-ion batteries with a para grass-derived SiOx/C anode and LFP cathode exhibited a capacity of 129 mAh g–1 at 0.1C and retained 80% of its capacity after 150 cycles at 1C. This study highlights the synthesis of anode materials from sustainable and cost-effective resources with favorable performance and stability.