Engineering Spin State in Spinel Co3O4 nanosheets by V‐Doping for Bidirectional Catalysis of Polysulfides in Lithium–Sulfur Batteries

• Published in: Advanced functional materials 2024-09, Vol.34 (37), p.n/a
• Main Authors: Zhou, Wei, Chen, Minzhe, Zhao, Dengke, Zhu, Chuheng, Wang, Nan, Lei, Wen, Guo, Yan, Li, Ligui
• Format: Article
• Language: English
• Subjects: Chemical bonds; Cobalt oxides; Doping; engineering spin state; Field theory; ligand field theory and molecular orbital theory; LiPSs bidirectional conversion; Lithium sulfur batteries; lithium‐sulfur battery; Molecular orbitals; Nanosheets; Polysulfides; Spinel; spinel Co3O4
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202402114

The slow bidirectional conversion and fast shuttling of lithium polysulfides (LiPSs) remain the main obstacles that inhibit the practical application of lithium sulfur batteries (LSBs). Here, by engineering the in‐spin state of spinel oxides, V doping‐induced hexagonal nanosheets (V‐Co3O4 NS) with intermediate spin state (IS, t2g5 eg1) can form stable bond order toward LiS* based on the ligand field theory and molecular orbital theory, thus effectively accelerating the sulfur conversion kinetics. Owing to these merits, the V‐Co3O4 NS modified separator base battery achieves a high areal capacity of 15.37 mAh cm−2 with sulfur loading of 15.4 mg cm−2, and it displays a low‐capacity attenuation of 0.015% each cycle at 3.0 C for 1900 cycles. By engineering the in‐spin state of spinel oxides, V doping‐induced hexagonal nanosheets (V‐Co3O4 NS) with intermediate spin state (IS, t2g5 eg1) could form stable bond order towards LiS*, which thus effectively accelerates the sulfur conversion kinetics and regulates homogeneous deposition of Li+. By using V‐Co3O4 NS to modify the PP separator, it achieves excellent cyclic stability in lithium sulfur batteries.