Synthesis of LiTiO₂ Nanocrystals/Ordered Mesoporous Carbon Composite Hosts for High-Performance Lithium-Sulfur...

Metal oxide nanocrystals/mesoporous carbon composite materials are promising in the energy storage field. However, the construction of stoichiometric ternary nanocrystals-functionalized mesoporous carbon materials remains a great challenge. Herein, the synthesis of ultradispersed and ultrasmall LiTiO₂ nanocrystals/ordered mesoporous carbon composites via a chelation-mediated multicomponent coassembly strategy is reported. In this case, the self-assembly into ordered mesostructures and the crystallization of nanoparticle processes can be decoupled by the molecular chelate strategy where citrate ligands can effectively inhibit the hydrolysis and phase separation of metal oxide precursors and confine the crystallization into nanocrystals without aggregation. The obtained 33%-LiTiO₂-OMC composites present a high specific surface area (≈912 m² g^-1), a large pore volume (≈0.62 cm³ g^-1), a uniform pore size (≈4.1 nm), and ultradispersed LiTiO₂ nanocrystals (≈3 nm). When loading 60% sulfur, the composites exhibit a high reversible capacity (966 mAh g^-1 after 100 cycles at 0.5C), an excellent rate capacity (700 mAh g^-1 at 5C), and a long-term cycling performance (63% retention after 1000 cycles at 5C). This method is very simple and reproducible, which paves a new way for the design and synthesis of functional mesoporous materials.