Controllable engineering magnetite nanoparticles dispersed in a hierarchical amylose derived carbon and reduced...

A straightforward and eco-friendly method is demonstrated to engineer magnetite (Fe₃O₄) nanoparticles well dispersed by an amorphous amylose-derived carbon (AMC) and reduced graphene oxide (RGO) framework. Naturally available amylose (AM) serves as both reducing agent for few-layered graphene oxide (GO) in the first mild redox coprecipitation system and precursor for small-sized pyrolytic AMC in the following thermal treatment. In particular, the presence of the AM molecules effectively limits the crystal growth kinetics for the akaganeite (FeOOH) in the intermediate FeOOH@AM/RGO sample, which contributes to the transformation to Fe₃O₄ nanoparticles with significantly controlled size in the final Fe₃O₄@AMC/RGO composite. As a result, both Fe₃O₄ nanoparticles and AMC domains are adjacently anchored on the larger sized RGO sheets, and a unique hierarchical structure has been engineered in the Fe₃O₄@AMC/RGO sample. Compared with the controlled Fe₃O₄@RGO sample, the Fe₃O₄@AMC/RGO composite exhibits remarkably enhanced initial coulombic efficiency, superior cycling stability and rate performance for lithium-ion storage. The mechanisms of the interaction between GO sheets and AM molecules as well as the inspiring electrochemical behaviors of the Fe₃O₄@AMC/RGO electrode have been revealed. The Fe₃O₄@AMC/RGO sample possesses good potential for scaling-up and finding applications in wider fields.