Biomass-Derived Hard Carbon with Optimized Pseudo-graphitic Domains and Closed Pores for High-Performance Sodium Storage

Hard carbon (HC) stands out as a competitive anode for sodium-ion batteries, combining abundant, sustainable precursors with desirable electrochemical properties. By employing a simple solution-based approach to control cellulose decomposition, we engineer curved pseudographitic domains with expanded interlayer spacing and rich closed pores from peanut shell precursors. The resulting PSHC-7 delivers 401 mAh g^–1 at 0.06 A g^–1, an initial Coulombic efficiency of 88.6%, 289 mAh g^–1 at 3.0 A g^–1, and 93.1% capacity retention over 4500 cycles. In situ Raman and in situ XRD reveal a multistep “adsorption–intercalation–pore filling” mechanism, while theoretical calculations confirm that hierarchical pores and pseudocapacitive effects enhance Na⁺ transport and storage. The full cells (NVP//PSHC-7) demonstrate practical applicability. This work provides an integrated experimental and theoretical framework linking precursor chemistry, microstructure, and electrochemical performance, offering a facile route to high-efficiency, durable, and cost-effective SIB anodes.