Doped silicon anode for lithium-ion batteries
AssigneePosi Energy-Silicon Power, LLC
InventorsDevendra K. Sadana, Joel P. De Souza, Brian Williams, Francis Christopher Farmer
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Abstract
An element to be used as an anode in a lithium-ion battery comprising an electrochemically lithiated thick or thin p or n-doped virgin single crystal Si with or without an oxide on the upper surface thereof. The lithiated structure further has a plurality of single crystalline p or n-doped Si particles dispersed over a non-lithium reactive reacting electrically conductive adhesive positioned atop a current collector.
Claims42
An element to be used as an anode suitable for use in a Li-ion battery comprising an electrochemically lithiated p or n-doped virgin single crystal Si having a layer with an upper surface devoid of an oxide;
- said p or n-Si being doped with either B for p-type Si, and P or As for n-type Si at concentrations of >2×1018 cm−3, and having a resistivity of <0.01 Ohm cm.
A structure suitable for use as an anode in a Li-ion battery comprising an electrochemically lithiated p or n-doped virgin single crystal Si having a layer with an upper surface devoid of an oxide;
- said p or n-Si being doped with either Boron for p-type Si, and Phosphorus or Arsenic for n-type Si at concentrations of >2×1018 cm−3 and having a resistivity of <0.01 Ohm/cm, atop a seed layer selected from Ti/Cu, Ti/Ni or Cr/Cu seed layer having a combined thickness of between about 20 nm and 500 nm, atop a current collector selected from Ni or Cu and having a thickness of between about 5 μm and 100 μm.
A Si anode structure suitable for lithiation to form a Li-ion battery comprising:
- a lithium metal electrode atop a liquid electrolyte soaked separator atop a surface layer comprising a single crystal p or n-doped structure having a layer with an upper surface devoid of or optionally containing SiO2 which is positioned atop a thin single crystal p or n-doped cathode serving as a negative electrode having a thickness of <1000 μm atop a seed layer selected from Ti/Cu, Ti/Ni or Cr/Cu seed layer having a combined thickness of between about 20 nm and 500 nm, atop a current collector selected from Ni or Cu and having a thickness of between about 5 μm and 100 μm.
A lithiated Si anode structure suitable for use in a Li-ion battery comprising a Li-containing surface layer having a thickness of between about 20 nm and 50 μm atop an electrodeposited mixture of Li and Li reacted Si, that has a thickness of between about 10 μm and 50 μm, atop a thin single crystal p or n-doped, has a thickness of between about 50 μm and 1000 μm, atop a seed layer selected from Ti/Cu, Ti/Ni or Cr/Cu having a combined thickness of between about 20 nm and 500 nm, atop a current collector selected from Ni or Cu and having a thickness of between about 5 μm and 100 μm, said structure having a high load capacity of greater than 20 mg/cm2 and a low capacity fade of less than 0.05% per cycle during first 100 cycles at a charge rate of C/10 or less.
The lithiated Si anode structure defined in claim 34 wherein said electrolyte is in solid state selected from polymer electrolytes, sulfide solid electrolytes (SSEs), argyrodite electrolytes, sulfur containing electrolytes including Li6PS5Cl, and lithium phosphorous oxynitride (LiPON) ceramic type electrolytes, and the separator is a polyolefin selected from polyethylene and polypropylene.
An anode structure comprising segmented single crystal p or n-doped Si particles forming a layer upper surface devoid of, or optionally containing said SiO2 particles, dispersed over an electrically conducting adhesive that is mixed with organic compounds selected from a non-lithium reacting materials, having a thickness between about 5 μm and 100 μm, atop a current collector having a thickness of between about 5 μm and 50 μm.
A structure adapted to form an anode suitable for use in a Li-ion battery after an electrochemical lithiation of said structure, comprising:
- a Li metal positive electrode layer having a thickness of between about 50 and 200 μm positioned immediately above a liquid electrolyte-soaked separator, jointly having a thickness of between about 5 μm and 25 μm, which is atop said single crystal p or n-doped particle layer, which is positioned atop a non-lithium reacting electrical conductive adhesive layer having a thickness of between about 5 μm and 100 μm atop a current connector having a thickness of between about 5 and 50 μm.
An electrochemical lithiation process comprising the following steps:
- Cleaning a single crystal p or n-Si substrate having a doping of approximately 1019 cm−3, and resistivity of approximately 0.005-ohm cm) in inorganic and organic solvents;
- Forming a half-cell to be used as an anode, comprising p-type single crystal Si that is doped with Boron (B) or n-type single crystal Si that is doped with Phosphorous (P) or Arsenic (As) at concentrations greater than 1018 cm−3, and a resistivity of less than 0.01 Ohm·cm, said anode in said half-cell optionally has no SiO2 surface oxide layer, or has an uneven, uniform or leaky surface SiO2 layers;
- said Li metal positive electrode layer having a thickness of between about 50 μm and 200 μm is positioned above a liquid electrolyte-soaked separator, having a thickness of between about 5 μm and 25 μm which is positioned atop said single crystal p or n-doped Si as the cathode serving as a negative electrode in a half-cell structure having a thickness of less than 1000 μm atop a current connector having a thickness of between about 5 μm and 25 μm, thus forming a Li-ion half-cell product;
- Performing a lithiation process on said Li-ion half-cell product by applying a constant current in the range of between about 1 and 10 mA/cm2 to obtain Li deposition on said Si surface;
- Fabricating a coin cell or a pouch cell with the lithiated Si anode.
An electrochemical lithiation process comprising the following steps:
- Cleaning a single crystal p-Si substrate having a doping of approximately 1019 cm−3, and resistivity of approximately 0.005-ohm cm. Perform electrochemical anodic etching of substrate in a 40% to 50% HF, with or without a surfactant to form a porous-Si region at a surface thereof;
- Forming a half-cell to be used as a porous Si anode, comprising p-type Si that is doped with Boron (B) at concentrations greater than 1018 cm−3, and a resistivity of less than 0.01 Ohm cm. said half-cell optionally having a porous silicon surface layer,
- Positioning a Li metal positive electrode layer having a thickness of between about 50 μm and 200 μm above a layer comprising a liquid electrolyte-soaked separator, having a thickness of between about 5 μm and 20 μm which is positioned atop said single crystal p or n-doped Si as a cathode serving as a negative electrode, having a thickness of less than 1000 μm atop a current connector having a thickness of between about 5 μm and 25 μm, thus forming a Li-ion half-cell product;
- Applying a constant current in the range of between about 1 and 10 mA/cm2 to obtain Li deposition on said Si surface to affect a lithiation process on said Li-ion half-cell product;
- Fabricating a coin cell or a pouch cell with the lithiated Si as an anode.
Dependencies are inferred from the claim text.