A monocrystal Fe3O4@ultrathin N-doped carbon core/shell structure: from magnetotactic bacteria to Li storage

Research on magnetotactic bacteria has attracted much attention in recent years because this kind of bacteria can produce magnetosome chains, which are composed of several Fe3O4 (or Fe3S4) monocrystals enveloped by a lipid bilayer. They can be a good precursor for fabricating nano-materials applied in energy storage systems, despite the fact that no one has yet done this. Herein, we made a bold attempt to fabricate nitrogen doped Fe3O4@C core–shell nano-materials translated from magnetosome chains in magnetotactic bacteria through a one-step carbonization process. The core–shell Fe3O4@C nano-materials, around 50 nm in size and covered with a 1.6 nm thick C shell, can be used as an anode for a lithium-ion battery. The initial Rct was only 49.9 Ω and the specific capacity stayed at 860 mA h g−1 at a current density of 2 A g−1 after at least 1000 cycles. This work opens up a new way to fabricate N-doped Fe3O4@C composite nanomaterials and it also provides a new choice of bio-precursors for fabricating energy storage materials.