Fe3O4 quantum dots embedded in porous carbon microspheres for long-life lithium-ion batteries

We report here Fe 3 O 4 quantum dots embedded Fe 3 O 4 @C electrode materials via a facile micelle-colloid template method for pushing forward the Li-ion battery technology. To improve uniform dispersion of Fe 3 O 4 quantum dots (5–10 nm) and create macropores in the carbon matrix, ferric micelle colloids of CTA + X −1 Fe 3+ with chelate adsorption of ferric colloids on CTAB micelle corona by electrostatic attraction has been developed in a resin layer. Thus, nanocrystalline Fe 3 O 4 and graphitic carbon matrix are mutually formed from the same texture during the pyrolysis process, resulting in a tightly tangled carbon-Fe 3 O 4 hybrids. The conformable embedment of Fe 3 O 4 quantum dots in carbon matrix can effectively prevent its loss and alleviate local tension stress for volume variation during change-discharge process. The well structure-designed Fe 3 O 4 @C electrode materials deliver a stable capacity of 601 mA h g −1 at 2 A g −1 even after 800 cycles. This work provides a new strategy for design of transition-metal-oxide based electrode materials for long-life lithium-ion batteries.