Anode battery materials and methods of making the same
In some embodiments, the present invention provides novel methods of preparing porous silicon films and particles for lithium ion batteries. In some embodiments, such methods generally include: (1) etching a silicon material by exposure of the silicon material to a constant current density in a solution to produce a porous silicon film over a substrate; and (2) separating the porous silicon film from the substrate by gradually increasing the electric current density in sequential increments. In some embodiments, the methods of the present invention may also include a step of associating the porous silicon film with a binding material. In some embodiments, the methods of the present invention may also include a step of splitting the porous silicon film to form porous silicon particles. Additional embodiments of the present invention pertain to anode materials derived from the porous silicon films and porous silicon particles.
1. An anode material for lithium ion batteries, wherein the anode material comprises:
a porous silicon particle comprising a silicon component,
wherein the silicon component comprises a plurality of pores in the silicon component,
wherein the plurality of pores comprise at least one pore that spans an entire thickness of the silicon component; and
a binding material associated with the silicon component, wherein the binding material comprises pyrolyzed polyacrylonitrile, and wherein the pyrolyzed polyacrylonitrile is infiltrated into the plurality of pores of the silicon component.
2. The anode material of claim 1 , wherein the plurality of pores comprise diameters between about 1 nanometer to about 5 micrometers.
3. The anode material of claim 1 , wherein the plurality of pores comprise diameters between about 500 nanometer to about 3 micrometers.
4. The anode material of claim 1 , wherein the porous silicon particle comprises a diameter that ranges from about 1 μm to about 50 μm.
5. The anode material of claim 1 , wherein the anode material has a capacity of at least about 600 mAh/g, and a coulombic efficiency of at least about 90%.
6. The anode material of claim 1 , wherein each of the plurality of pores span an entire thickness of the silicon component.