Confined space self-propagating room temperature synthesis of carbon-encapsulated Fe₃O₄ nanocrystals and its lithium storage performance

Abstract

A self-propagating reaction between ferrocene and iron nitrate nonahydrate that is initiated at room temperature is discovered. Amorphous carbon-encapsulated Fe3O4 nanocrystals (Fe3O4@C) can be one-step prepared in an autoclave through this reaction. The equiaxed Fe3O4 nanocrystals have typical dimensions in the range of 5–60 nm with a median size of 24.1 nm, and their weight percent is up to 82.3%. The course of the reaction is recorded, and the formation mechanism of Fe3O4@C with the core–shell structure is proposed. The scaling-up synthesis is also achieved, and 52.1 g of the Fe3O4@C can be obtained in a single batch. The shock wave appeared in the fast gas release self-propagating reaction in confined space plays a decisive role in the preparation of homogeneous Fe3O4@C with a core–shell structure. The Fe3O4@C anode shows excellent capacity retention with a high specific capacity of 494 mAh g−1 at 1 A g−1 in the 200th cycle.

Toward materials-by-design: achieving functional materials with physical and chemical effects

“…In addition, the existing forms of reactants, i.e. gas, solid or liquid, can also influence the chemical reaction and crystallization, which lead to different end-materials [27][28][29]. Various physical, chemical, and physical-chemical methods have been developed to nanomaterials with different properties and functionalities [30][31][32].…”