Confined Synthesis of Amorphous Al2O3 Framework Nanocomposites Based on the Oxygen‐Potential Diagram as Sulfur Hosts for Catalytic Conversion

Abstract

Abstract Sulfur cathodes in Li–S batteries suffer significant volumetric expansion and lack of catalytic activity for polysulfide conversion. In this study, a confined self‐reduction synthetic route is developed for preparing nanocomposites using diverse metal ions (Mn2+, Co2+, Ni2+, and Zn2+)‐introduced Al‐MIL‐96 as precursors. The Ni2+‐introduced Al‐MIL‐96‐derived nanocomposite contains a “hardness unit”, amorphous aluminum oxide framework, to restrain the volumetric expansion, and a “softness unit”, Ni nanocrystals, to improve the catalytic activity. The oxygen‐potential diagram theoretically explains why Ni2+ is preferentially reduced. Postmortem microstructure characterization confirms the suppressive volume expansion. The in situ ultraviolet–visible measurements are performed to probe the catalytic activity of polysulfide conversion. This study provides a new perspective for designing nanocomposites with “hardness units” and “softness units” as sulfur or other catalyst hosts.

Keywords

• amorphous aluminum oxide
• catalysis
• confined synthesis
• Ni nanocrystals
• oxygen‐potential diagram