Effect of precursor selection on the structure and Li-storage properties of wood-based hard carbon thick electrodes

Herein, balsa wood, poplar wood, and birch wood were selected to systematically study precursors on the structure and Li-storage properties of wood-based hard carbon thick electrodes (WHCTEs). After carbonization, the densities of balsa, poplar, and birch carbon (Bal-W, Pop-W, and Bir-W) reach 99.29, 279.13, and 608.14 mg cm⁻3, respectively. The specific surface areas of Bal-W, Pop-W, and Bir-W are 798, 729, and 609 m2 g⁻1, respectively. Bal-W is rich in mesopores at 2–4 nm; Pop-W also has a certain amount of mesopores; while Bir-W has almost no mesopores but large numbers of micropores concentrated at 1.2 and 1.6 nm. In the battery test, due to the highest mass loading, Bir-W retained the largest remaining capacity among the three samples after 200 cycles at 1 mA cm⁻2. The remaining capacities of Bal-W, Pop-W, and Bir-W are 12.27, 34.15, and 41.03 Ah L⁻1, respectively. It is found that mass loading, specific surface area, and pore size distribution have a greater influence on the electrode capacity performance. In addition, the kinetic features of the Li-ion storage of WHCTEs were studied. This work may provide an important reference for the field of WHCTEs for alkali metal ion batteries and can promote its practical application.