Synergistic improvement of the sulfur redox reaction by MOF-driven dual-defect polyhedral Mn-doped Co1-xS embedded in an N-doped carbon composite host for practical lithium-sulfur batteries

• Published in: Electrochimica acta Vol. 506; p. 145070
• Main Authors: Dong, Yutao, Peng, Huaiqi, Jin, Ziqian, Ma, Shiyu, Han, Lifeng, Sheng, Xia, Ren, Yunlai, Xie, Lixia, Zheng, Xianfu, Li, Xin, Zhang, Jianmin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2024
• Subjects: Derivative; Dual-defect; Lithium-sulfur battery; Metal–organic frameworks; Synergistic interaction; Derivative; Dual-defect; Lithium-sulfur battery; Synergistic interaction; Metal–organic frameworks
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2024.145070

In the quest for practical sulfur hosts for lithium-sulfur batteries, a novel approach has been delineated. By meticulously adjusting the Mn:Co (1:5/1:9/1:1) ratio and the sulfidation temperature, a series of nitrogen-doped carbon nanopolyhedron composites have been synthesized, denoted as 1:9 Mn-Co1-xS-NC@NC, 1:5 Mn-Co1-xS-NC@NC, 1:1 Mn-Co1-xS-NC@NC, and Co1-xS-NC@NC. These materials, inheriting the polyhedral shape and a novel cavity structure from their precursors, exhibit enhanced lithium polysulfide adsorption and catalytic activity due to the introduction of Mn heteroatoms and cobalt vacancies. The resultant S@1:9 Mn-Co1-xS-NC@NC cathode excels in electrochemical performance, delivering an initial discharge capacity of 999.37 mA h g−1 at 1 C, and sustaining 715.65 mA h g−1 over 100 cycles. Notably, at an elevated sulfur loading of 3.05 mg cm−2 (E/S, 14.5 uL g−1), the cathode retains an areal capacity of 3.24 cmmA h cm−2 (corresponding specific capacity of 1067.59 mA h g−1) after 61 cycles at 0.2 C. The synergistic effect of manganese dopants and cobalt vacancies confers superior adsorptive and catalytic properties, presenting a promising avenue for the development of sulfur host materials with tailored morphologies and defect-rich structures. Nano-polyhedrons with a core-shell structure featuring manganese doping and cobalt vacancies, denoted as Mn-Co1-xS-NC@NC, have been successfully synthesized and employed as host materials for lithium-sulfur batteries. The 1:9 Mn-Co1-xS-NC@NC host material significantly improves the cycling performance of lithium-sulfur batteries through the synergistic effects of spatial confinement, chemical adsorption, and catalysis, enabling stable long-term cycling at 2 C. [Display omitted]