Advanced multielement (O, N, S) modified strategies for pitch-based carbon anodes toward both lithium and sodium storage

Abstract

Pitch is a commonly used industrial by-product precursor in the production of anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, achieving efficient utilization of waste pitch poses a challenge for recycled materials. To address this issue, we used simple multielement modification and obtain the pitch-based carbon doped with oxygen (O), nitrogen (N), and sulfur (S). Our work reveals that pitch with high softening point tends to form the crosslinked structure during pre-oxidation. Moreover, in proximity to the defects induced by oxygen functionalities, the introduction of nitrogen and sulfur can jointly impact on the diffusion kinetics of lithium/sodium, and it is demonstrated by enhancing lithium adsorption and sodium desorption from the defects. In comparison to the conventional one-step carbonization approach, the modified anodes significantly improve the rate performance of the LIBs (61.11 mAh g−1 to 222.90 mAh g−1 at 5 A g−1) and the initial Coulombic efficiency (ICE) of SIBs (41.74%–66.40%). Our study explores the link between softening points and oxygen functionalities, as well as the effect of introducing various heteroatoms on the properties and diffusion kinetics of LIBs and SIBs, providing a reference for other materials to obtain anodes with high compatibility.