Revealing the sodium storage behavior of biomass-derived hard carbon by using pure lignin and cellulose as model precursors

Abstract

Lignin and cellulose are dominant components in biomass and hold the key for preparing hard carbons. Identifying the sodium storage behaviors of sole lignin/cellulose-derived hard carbons is significant for choosing optimal biomass precursors. Herein, milled-wood lignin and microcrystalline cellulose are used as model precursors to prepare hard carbons and the corresponding sodium storage performances are investigated to understand the contribution of each biomass component. Compared with lignin-derived carbon, cellulose-derived carbon enables a larger initial Coulombic efficiency of 87.1%, a higher reversible capacity of 343.3 mA h g⁻¹ at 0.02 A g⁻¹ and a good rate capability of 49.2 mA h g⁻¹ at 1 A g⁻¹ owing to larger L_a, lower I_D/I_G values and higher sp²C, CO contents with the benefit of enhancing the conductivity, plateau capacity, and the rapid diffusion of sodium ions. The excellent performance of cellulose-derived carbon provides guidance on the choice of biomass precursors for high-performance sodium-ion batteries.