Single-step pyrolysis of Stipa Tenacissima fibers to hard carbon: A potential route for sodium-ion battery anodes

Hard Carbon (HC) has emerged as a viable candidate for the negative electrode material in sodium-ion batteries (SIBs). This study focuses on the development of a novel HC-negative electrode derived from the pyrolysis of Stipa tenacissima fibers (STF). Prior to pyrolysis, STF underwent a hot water wash pre-treatment, and various pyrolysis temperatures (800 degrees C, 1000 degrees C, and 1300 degrees C) were investigated to elucidate their influence on HC properties and performance. Structural analysis revealed significant differences in the HC structure, highlighting a direct correlation between capacity improvement and the size of accessible micropores for sodium insertion. Composite electrodes were assembled and evaluated in non-aqueous sodium half-cells to assess HC's performance. Notably, increasing the pyrolysis temperature resulted in higher reversible capacity (RC). Specifically, HC prepared at 1300 degrees C exhibited an RC of 270 mAh g(-1), initial coulombic efficiency (ICE) of approximately 60 %, and exceptional reversibility with 99 % capacity retention after 90 cycles at a 25 mA g(-1) of current density (CD). These results surpassed those obtained with HC prepared at 800 degrees C and 1000 degrees C. Moreover, this study explores the biological, biochemical, biophysical, and structural advantages conferred by STF, making it a promising component in SIBs, with the ultimate goal of establishing long-lasting, high-performance battery systems.