Bovine serum albumin assisted synthesis of Fe3O4@C@Mn3O4 multilayer core–shell porous spheres as anodes for lithium ion battery

The novel uniform Fe3O4@[email protected]3O4 multilayer core–shell porous spheres for used in lithium–ion batteries (LIBs) have been synthesized with utilizing bovine serum albumin (BSA) as carbon source by hydrothermal process. Fe3O4 porous spheres are coated by carbon and Mn3O4 nanolayer, when manganese ion and iron ion could be adsorbed on BSA. It is indicated that chelation of protein and metal is constructed between the metal ions and the atom with lone pair electrons on the surface of the protein amino acid. And the chelation is connected by the nitrogen atoms in histidine of BSA and the Fe2+, Mn2+ in the metal ions. As an anode material for LIBs, Fe3O4@[email protected]3O4 core–shell nanostructure particles show a high initial capacity of 1261 mAh g−1 at the current density of 0.1 C, a reversible capacity of approximately 987 mAh g−1 after 200 cycles, which possess excellent cycling stability. The enhanced electrochemical properties are mainly ascribed to the core/shell architecture between the different metal oxides with carbon interlayer, which can effectively improve the electric conductivity, active phase, the synergy between different metal oxides. And also, the porous structure could help anodes for buffering the dramatic volume change of active material for improving electrochemical performance for LIBs.