Carbon anode for lithium ion electrochemical cell
First Claim
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1. A method of preparing an electrochemical cell and controlling the first cycle capacity loss of said electrochemical cell, which method comprises the steps of:
- (a) forming an intercalation based anode comprising graphite particles by a process comprising;
(i) providing an initial graphite composition;
(ii) measuring the percentage of 3R phase graphite present in said initial graphite composition;
(iii) increasing the percentage of 3R phase graphite in said initial graphite composition to form a second graphite composition which comprises graphite particles having an average diameter of less than 75 μ
m;
(b) providing a cathode; and
(c) interposing a non-aqueous electrolyte containing a solvent and lithium salt between the anode and cathode.
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Abstract
Increasing the percentage of the 3R phase present in graphite reduces the first capacity loss of anodes employing the so modified graphite. Conversion of 2H phase graphite to 3R phase graphite can be achieved by grinding graphite. Non-aqueous solid electrochemical cells with improved performance can be fabricated by employing intercalation based carbon anodes comprising graphite with high percentage of 3R. When employed in an electrochemical cell, the first cycle capacity loss of only about 10%.
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Citations
20 Claims
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1. A method of preparing an electrochemical cell and controlling the first cycle capacity loss of said electrochemical cell, which method comprises the steps of:
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(a) forming an intercalation based anode comprising graphite particles by a process comprising; (i) providing an initial graphite composition; (ii) measuring the percentage of 3R phase graphite present in said initial graphite composition; (iii) increasing the percentage of 3R phase graphite in said initial graphite composition to form a second graphite composition which comprises graphite particles having an average diameter of less than 75 μ
m;(b) providing a cathode; and (c) interposing a non-aqueous electrolyte containing a solvent and lithium salt between the anode and cathode. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of preparing an electrochemical cell and reducing the first capacity loss of said electrochemical cell, which method comprises the steps of:
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(a) forming an intercalation based anode comprising graphite particles by a process comprising; (i) providing an initial graphite composition; (ii) increasing the percentage of 3R phase graphite present in said initial graphite composition to form a second graphite composition which comprises graphite wherein at least 20 percent of the graphite is 3R phase graphite; (b) providing a cathode; and (c) interposing a non-aqueous electrolyte containing a solvent and lithium salt between the anode and cathode and wherein the electrochemical cell has a first cycle loss of less than about 15% and a specific capacity of greater than 300 mAh/g. - View Dependent Claims (8, 9, 10, 11)
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12. A method of preparing an intercalation based carbon anode comprising graphite particles and controlling the first cycle capacity loss when employed in an electrochemical cell, which method comprises the steps of:
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providing an initial graphite composition; measuring the percentage of 3R phase graphite present in said initial graphite composition; and increasing the percentage of 3R phase graphite in said initial graphite composition to form a second graphite composition which comprises graphite particles having an average diameter of less than 75 μ
m wherein the second graphite composition has a lower first cycle capacity loss than the initial graphite composition when employed in the electrochemical cell. - View Dependent Claims (13, 14, 15, 16)
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17. A method of preparing an intercalation based carbon anode comprising graphite wherein the anode has less than about 10 percent first cycle capacity loss when employed in an electrochemical cell, which method comprises the steps of:
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providing an initial graphite composition; and increasing the percentage of 3R phase graphite in said initial graphite composition to form a second graphite composition which comprises graphite wherein at least about 20 percent of the graphite is 3R phase graphite wherein the second graphite composition has a lower first cycle capacity loss than the initial graphite composition when employed in the electrochemical cell. - View Dependent Claims (18, 19, 20)
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Specification