Biomass Corn Cob-Derived Hard Carbons via Joule Heating for Sodium-Ion Storage

Hard carbon (HC) materials are widely recognized as one of the most promising anode candidates for sodium-ion batteries (SIBs). Biomass-derived HC materials particularly possess the advantages of abundant sources, low cost, and high sodium-ion (Na+) storage capacity. In this work, the agricultural byproduct corn cob is employed as a raw material to prepare HC samples via a facile two-step approach of pre-carbonization and Joule heating treatment. Among the prepared HC samples, the CHC-1400 sample exhibits the optimal physiochemical properties. As a result, the corresponding CHC-1400 electrode not only delivers the highest initial reversible capacity of 263 mAh g−1 with a corresponding initial coulombic efficiency (ICE) of 72% at 0.2 C, but maintains a high capacity retention of 91% after 300 cycles. The Na+ storage mechanism for the HC samples has thus been revealed. This study introduces a novel, time-saving, and cost-effective protocol for synthesizing biomass-derived HC anode materials, which is of great significance to the advancement of SIBs.