Green self-derived templating preparation of nitrogen, sulfur co-doped porous carbon/tin composites with synergistic effect towards high-performance lithium-ion batteries

Abstract

Although single-heteroatom doped porous carbon/tin (Sn) composites have been extensively studied, an overall understanding of the effects of dual-heteroatoms doped porous carbon on the lithium storage properties of Sn is still insufficient. Herein, we provide a green self-derived templating strategy to synthesize the nitrogen, sulfur co-doped porous carbon/Sn composites (Sn/NSPC) with synergistic effect through one-step carbonization. The key to this approach is the self-generation of Na2CO3 template, and it is apt to eliminate with water directly. The resultant NSPC can prevent the agglomeration of Sn particles. The synergistic effect is confirmed by density functional theoretical (DFT) calculations, revealing that N, S co-doped improves the electronic conductivity. The lithium storage mechanism and structural stability of Sn/NSPC electrode are researched via in-situ XRD and ex-situ XPS. The obtained electrode affords a discharge capacity (200 cycles, 712.6 mAh/g at 0.1 A/g) and long-life cyclability (2000 cycles, 330.1 mAh/g at 3 A/g). Additionally, the Sn/NSPC||LiCoO2 full cell achieves excellent discharge capacity (572.6 mAh/g at 0.1 A/g) while remaining impressive cyclability (440.6 mAh/g at 1 A/g). This green and eco-friendly approach may be extended to the preparation of other heteroatom-doped carbon/Sn composites.