Hierarchical Porous Carbon Anode Materials Derived from Rice Husks with High Capacity and Long Cycling Stability for Sodium‐Ion Batteries

Abstract Compared with the cathode materials, the research on the anode materials of the sodium‐ion batteries has lagged behind. Therefore, development of the anode materials with high capacity, long life, and excellent rate properties is the key to unlocking the practical application for sodium‐ion batteries. This study presents the preparation of hierarchical porous hard carbon as an active anode material from rice husks. The as‐synthesized materials are characterized by X‐ray diffraction, N 2 adsorption, Raman spectra, scanning electron microscopy and transmission electron microscopy. These porous hard carbon materials exhibit a high specific surface area and are promising for reversible sodium storage. Galvanostatic studies show that the specific initial capacities of all samples were in the range of 130–300 mA h g −1 at a current density of 100 mA g −1 between 0.01 V and 2.3 V. Compared to the other samples, the hard carbon materials prepared at 800 °C from rice husk (RHPC‐800) can deliver a high reversible capacity of 274 mA h g −1 at a current density of 25 mA g −1 , maintain a capacity of approximately 260 mA h g −1 , and retain 92.7 % of its capacity after 500 cycles. This excellent electrochemical performance of the as‐prepared RHPC‐800 material is attributed to the high specific surface area and low charge transfer resistance.