Wood-Derived Carbon with Selectively Introduced C═O Groups toward Stable and High Capacity Anodes for Sodium Storage

Biomass-derived carbon is a promising sustainable anode material for sodium-ion batteries (SIBs). Although the electrochemical performance can be improved by introducing functional groups, the selective introduction of single functional groups into biomass carbon remains difficult. Here, we overcome this challenge by developing a wood-derived carbon with selectively introduced C═O groups by combining tetramethoxysilane (TMOS) with wood cellulose pulps. The integration of TMOS introduces abundant C═O groups into the carbon during the polycondensation and pyrolysis process. The C═O groups play a dominant role in anode surface-controlled processes, and this leads to improvements in pseudo-capacity and fast electrode process kinetics. Besides, the introduction of C═O groups generates oxygen functional active sites that promote Na⁺ adsorption and creates a sufficiently large graphene interlayer distance. The as-obtained carbon shows a high capacity of 330 mAh g^-1 at 40 mA g^-1 and excellent cycling stability. Moreover, our strategy is simple and uses wood cellulose pulps as precursors. It therefore enables low-cost and large-scale synthesis of carbon anode materials for SIBs.