Method of fabricating structured particles composed of silicon or silicon-based material and their use in lithium rechargeable batteries
First Claim
1. A method of treating silicon to form elongate structures on a treated surface, the method comprising a nucleation step in which metal is deposited on the silicon surface and an etching step in which silicon underlying the deposited metal is etched, whereina. the nucleation step comprises exposing a silicon containing material to a solution comprising HF at a concentration of less than 5M and0.002 to 0.2M of metal ions capable of nucleating on and forming a porous layer comprising regions of elemental metal on the silicon surface;
- andb. the etching step comprisesi. exposing the silicon surface comprising regions of elemental metal to a solution comprising HF at a concentration of greater than 5M and 0.001 to 0.70M of an oxidant selected from the group comprising O2, O3, H2O2, the acid, ammonium or alkali metal salt of NO3−
, S2O82−
, B4O72−
and ClO4−
or a mixture thereof; and
ii. adding oxidant to the solution during etching to maintain the concentration of oxidant within the above range.
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Abstract
A method for treating silicon to form pillars, especially for use as the active anode material in Li-ion batteries, is disclosed. The process is simple to operate on a commercial scale since it uses a solution containing only a small number of ingredients whose concentration needs to be controlled and it can be cheaper to operate than previous processes. The solution includes: 0.01 to 5M HF 0.002 to 0.2M of metal ions capable of nucleating on and forming a porous layer comprising regions of elemental metal on the silicon surface; 0.001 to 0.7M of an oxidant selected from the group O2, O3, H2O2, the acid, ammonium or alkali metal salt of NO3−, S2O82−, NO2−, B4O72− and ClO4− or a mixture thereof. The treated silicon is suitably removed from the solution.
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Citations
28 Claims
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1. A method of treating silicon to form elongate structures on a treated surface, the method comprising a nucleation step in which metal is deposited on the silicon surface and an etching step in which silicon underlying the deposited metal is etched, wherein
a. the nucleation step comprises exposing a silicon containing material to a solution comprising HF at a concentration of less than 5M and 0.002 to 0.2M of metal ions capable of nucleating on and forming a porous layer comprising regions of elemental metal on the silicon surface; - and
b. the etching step comprises i. exposing the silicon surface comprising regions of elemental metal to a solution comprising HF at a concentration of greater than 5M and 0.001 to 0.70M of an oxidant selected from the group comprising O2, O3, H2O2, the acid, ammonium or alkali metal salt of NO3−
, S2O82−
, B4O72−
and ClO4−
or a mixture thereof; andii. adding oxidant to the solution during etching to maintain the concentration of oxidant within the above range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification
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- Resources
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Current AssigneeNexeon Limited
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Original AssigneeNexeon Limited
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InventorsGreen, Mino, Liu, Feng-Ming, Jiang, Yuxiong, Mills-Lamptey, Benjamin Odarkwei, Stevens, Valerie Elizabeth Dawn
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Primary Examiner(s)Deo, Duy
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Application NumberUS13/639,395Publication NumberTime in Patent Office1,187 DaysField of SearchNoneUS Class Current438/745CPC Class CodesC09K 13/08 containing a fluorine compoundC23F 1/16 Acidic compositions C23F1/4...H01L 21/30604 Chemical etchingH01M 4/0492 Chemical attack of the supp...H01M 4/38 of elements or alloysY02E 60/10 Energy storage using batteries
