Rechargeable sodium-ion batteries usually suffer from accelerated electrode destruction at high temperatures and high synthesis costs of electrode materials. Therefore, it is highly desirable to explore novel organic electrodes considering their cost-effectiveness and large adaptability to volume changes. Herein, natural biomass, pristine lignin, is employed as the sodium-ion battery anodes, and their sodium storage performance is investigated at room temperature and 60 ℃. The lignin anodes exhibit excellent high-temperature sodium-ion battery performance. This mainly results from the generation of abundant reactive sites (C=O) due to the high temperature-induced homogeneous cleavage of the C_β–O bond in the lignin macromolecule. This work can inspire researchers to explore other natural organic materials for large-scale applications and high-value utilization in advanced energy storage devices.