RESUMO
Sulfur (S) is an efficient dopant to enhance the sodium storage of carbon, yet the conventional in-situ/post treatments cause unstable S configuration or lower S content, and hence unsatisfied electrochemical performance. Herein, we investigate sulfurization at various cross-link state of coal tar pitch (CTP) (pristine, coke, and carbonized states), and the microstructure of the products (SCTP). Experimental and calculational results reveal that introducing S in the coke state of CTP is essential for achieving abundant and stable C-Sx-C bonds between carbon layers. Moreover, this innovative strategy not only achieves a high S content, but also avoids the liquid carbonization, resulting in a hierarchically porous structure with a small particle size. As a result, the SCTP delivers a sodium storage capacity of 318 mA h g-1 at 0.1 A g-1 after 200th cycle, and the capacity maintains 207 mA h g-1 with capacity retention of 99 % after 1000th cycle at 2.0 A g-1, in half-cells. Moreover, the sample shows a considerable discharge capacity of 328 mA h g-1anode at 0.05 A g-1 in full-cells. Consequently, this approach offers a novel pathway for large-scale production of thermoplastic-derived carbons in battery industry.
RESUMO
Rapid carbonization within only 10 min achieves the balance of sodium storage sites and electronic conductivity for MOF-derived carbon, delivering excellent sodium storage properties. This work supplies a novel and environment-friendly method to treat MOF-derived materials in the field of electrochemistry.
RESUMO
Different oxygen functionalization processes occur for N-doped soft carbon (N-SC) and hard carbon (N-HC), and there may be a competitive relationship between the formation of pyridinic-N and CîO groups. For N-SC, abundant CîO groups and defects bring excellent Na+ storage performance and cycling stability, especially at high current densities.
