DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This is a final office action in response to Applicant’s remarks and amendments filed on March 30, 2026. Claims 1 and 8 are currently amended. Claim 7 is canceled. Claims 9-11 are newly added. Claims 1, 4, 5 and 8-11 are pending review in this action.
New grounds of rejection necessitated by Applicant’s amendments are presented below.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 4, 5, 8 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pre-Grant Publication No. 2013/0089791, hereinafter Chang in view of U.S. Pre-Grant Publication No. 2009/0252864, hereinafter Carel, Japanese Patent Publication No. 2003/208893A, hereinafter Ka, U.S. Pre-Grant Publication No. 2018/0269519, hereinafter Jo and U.S. Pre-Grant Publication No. 2018/0069235, hereinafter Lee. (A machine translation of Ka was provided with a prior office action).
Regarding claim 1, Chang teaches a manufacturing method of an anode active material for a lithium secondary battery.
The method comprises a step of homogeneously mixing graphite (“carbon-based particle”), silicon particles and pitch (“first carbon precursor”) (paragraph [0074]). Chang does not mention any solvent – therefore it is understood that the step is performed without a solvent.
The step of “homogeneous mixing” is considered equivalent to the instantly claimed sequential steps of “forming a mixture” and “stirring”. Alternatively, it would have been obvious to the ordinarily skilled artist that to homogenously mix materials, one would need to first create the mixture of the materials and then stir the mixture.
This step results in forming a “first composite precursor” in which the silicon particles are dispersed in the polymer material and are positioned on the graphite (“carbon-based particle”) (paragraph [0074]).
The method further comprises a step of thermally treating (“firing”) the “first composite precursor” (paragraph [0074]). After firing, the anode active material comprises the graphite (“carbon-based particle”) and a composite layer positioned on the graphite (“carbon-based particle”) and including silicon particles dispersed in a carbon matrix.
Chang fails to: 1) teach a step of adding a second carbon precursor to the “first composite precursor” prior to the firing step; 2) report on the degree of crystallinity of the silicon particle in the composite layer and 3) teach an outermost carbon coating layer positioned on the composite layer.
Regarding 1), additional application of coverage material following an initial application of coverage material for the purpose of ensuring sufficient coverage is a routine practice. Moreover, the sequential addition of pitch for the purpose of ensuring sufficient coverage in materials similar to Chang’s is also known the in art – see, e.g. Carel. Carel teaches forming an anode active material comprising graphite particles coated with silicon particles embedded in pitch and subsequently carbonized (paragraphs [0026, 0033]). Carel teaches sequentially adding portions of pitch until the pitch coating is considered sufficient (paragraph [0027]). Following this the material is carbonized (“fired”).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to incorporate a second step of pitch addition directly after the stirring step and prior to the firing step for the purpose of ensuring sufficient pitch coverage of the graphite (“carbon-based particle”) and silicon by the pitch. In the combination of Chang and Carel, the pitch in the second step of pitch addition would be a “second carbon precursor”.
Regarding 2), it is well-known in the art to use silicon particles with defined crystallinity as anode active materials – see, e.g. Ka, who teaches silicon particles with a preferred crystalline content (“degree of crystallinity”) of 10% to 60% (paragraph [0012, 0022]). Ka teaches that the reduced crystallinity minimizes the volume expansion of the active material upon lithium ion intercalation and thus improves the performance of the battery.
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to ensure that the crystallinity of the silicon particles after firing is within the range 10% to 60% for the purpose of minimizing the volume expansion of the silicon during lithium ion intercalation and thus achieving superior performance in the battery.
Regarding 3), the presence of an outermost carbon coating layer positioned on a composite layer including silicon particles dispersed in a carbon matrix is a known configuration in the art.
Jo teaches an analogous anode active material including a graphite core (117) and a composite coating layer positioned on the graphite core (117). Jo’s material is prepared in a manner analogous to Chang involving mixing silicon particles, graphite core and a polymer material as a carbon precursor and then firing (paragraph [0159]).
In Jo’s material, the composite coating layer includes an inner band formed of silicon particles (111) dispersed within a carbon layer matrix (115) (paragraphs [0112-0114, 0124] and figure 3). This inner band is equivalent to the instantly claimed “composite layer”.
The composite coating layer further has an outer band, which does not include the silicon particles (111) and only includes the carbon matrix material (115). This outer band of the composite coating layer is equivalent to the instantly claimed “outermost carbon coating layer” positioned on the “composite layer” (figure 3).
Jo teaches that the diameter of the crystalline carbon particle (117) may be in the range 300 nm to 30 µm (paragraph [0116]). Jo further teaches that the diameter of the full particle (100) may be 500 nm to 35 µm (paragraph [0120]).
It can thus be calculated that the combined thickness of the “composite layer” and the “outermost carbon coating layer” is in the range 100 nm to 2.5 µm.
The thickness of the “composite layer” is determined by the diameter of the silicon particles (figure 3). Jo teaches that the diameter of the silicon particles is in the range 20 nm to 200 nm (paragraph [0078]).
Then, the thickness of the “composite layer” is approximately in the range 20 nm to 200 nm and the thickness of the “outermost carbon coating layer” is in the range 80 nm to 2.3 µm.
The function of the carbon is to suppress the volume expansion of the silicon particles during charging and discharging (paragraph [0121]).
See, also Lee who teaches an anode active material including a graphite particle (1) and a composite coating layer positioned on the graphite particle (1). The composite coating layer includes an inner band formed of silicon particles (2) covered in a first carbon coating layer (3) and further covered by a second carbon coating layer (4) (paragraph [0041] and figure 1). The second carbon coating layer (4) has a thickness of 100 nm to 1.5 µm (paragraph [0060]). The purpose of the second carbon coating layer (4) is to control the volume change of the silicon upon charge and discharge and to maintain the shape of the particles (paragraph [0059]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to use Chang’s method to form an anode active material including the graphite (“carbon-based particle”), the “composite layer” positioned on the graphite (“carbon-based particle”) and including silicon particles dispersed in a carbon matrix and an “outermost carbon coating layer” positioned on the “composite layer” and having a thickness in the range 80 nm to 2.3 µm for the purpose of controlling the volume change of the silicon particles occurring during charge and discharge and thus maintaining the shape of the particles.
The optimum range for the thickness of the “outermost carbon coating layer” in Chang as modified by Jo and Lee overlaps the instant range of 200 nm to 1 µm. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 4, Chang teaches that the graphite (“carbon-based particle”) is present at 90 wt%, the silicon is present at 2 wt% and the pitch (“first carbon precursor”) is present at 8 wt%. Chang as modified by Carel teaches that an overall total pitch may be in the range 10 wt% to 50 wt% (paragraph [0027]).
The optimum range for the sum of silicon and “first carbon precursor” and “second carbon precursor” in Chang as modified by Carel overlaps the instant ranges of 5 wt% to 50 wt% and 5 wt% to 40 wt%, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 5, Chang teaches that the silicon is present at 2 wt% (paragraph [0074]).
Regarding claim 8, Chang teaches a heat-treatment (“firing step”).
Carel teaches that carbonization may occur at a temperature in the range 600°C to 1400°C (paragraph [0033]).
Chang fails to teach that the heat-treatment (“firing step”) is performed at a temperature in the range 600°C to 700°C.
Jo teaches that using amorphous silicon particles and controlling the firing temperature permits for controlling the crystallinity of the final material and thus improves the performance of the battery (paragraphs [0048, 0123]). Jo teaches that suitable carbonizing temperatures are in the range 500°C – 800°C (paragraph [0096]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to use a firing temperature in the range 600°C – 800°C for the purpose of being able to carefully control the crystallinity of the active material and thus improving the performance of the battery.
The optimum firing temperature range in Chang as modified by Carel and Jo overlaps the instant application's optimum range of 600°C – 700°C. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 11, in the combination of Chang, Jo and Lee the thickness of the “composite layer” is determined by the diameter of the silicon particles.
In Chang’s example, the silicon particles have a diameter of 300 nm (paragraph [0074]). The composite layer would then have a thickness of about 300 nm.
Claims 1, 4, 5 and 8-11 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pre-Grant Publication No. 2013/0089791, hereinafter Chang in view of U.S. Pre-Grant Publication No. 2009/0252864, hereinafter Carel, U.S. Pre-Grant Publication No. 2011/0311873, hereinafter Schulz, U.S. Pre-Grant Publication No. 2018/0269519, hereinafter Jo and U.S. Pre-Grant Publication No. 2018/0069235, hereinafter Lee.
Regarding claim 1, Chang teaches a manufacturing method of an anode active material for a lithium secondary battery.
The method comprises a step of homogeneously mixing graphite (“carbon-based particle”), silicon particles and pitch (“first carbon precursor”) (paragraph [0074]). Chang does not mention any solvent – therefore it is understood that the step is performed without a solvent.
The step of “homogeneous mixing” is considered equivalent to the instantly claimed sequential steps of “forming a mixture” and “stirring”. Alternatively, it would have been obvious to the ordinarily skilled artist that to homogenously mix materials, one would need to first create the mixture of the materials and then stir the mixture.
This step results in forming a “first composite precursor” in which the silicon particles are dispersed in the polymer material and are positioned on the graphite (“carbon-based particle”) (paragraph [0074]).
The method further comprises a step of thermally treating (“firing”) the “first composite precursor” (paragraph [0074]). After firing, the anode active material comprises the graphite (“carbon-based particle”) and a composite layer positioned on the graphite (“carbon-based particle”) and including silicon particles dispersed in a carbon matrix.
Chang fails to: 1) teach a step of adding a second carbon precursor to the “first composite precursor” prior to the firing step; 2) report on the degree of crystallinity of the silicon particle in the composite layer and 3) an outermost carbon coating layer positioned on the composite layer.
Regarding 1), additional application of coverage material following an initial application of coverage material for the purpose of ensuring sufficient coverage is a routine practice. Moreover, the sequential addition of pitch for the purpose of ensuring sufficient coverage in materials similar to Chang’s is also known the in art – see, e.g. Carel. Carel teaches forming an anode active material comprising graphite particles coated with silicon particles embedded in pitch and subsequently carbonized (paragraphs [0026, 0033]). Carel teaches sequentially adding portions of pitch until the pitch coating is considered sufficient (paragraph [0027]). Following this the material is carbonized (“fired”).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to incorporate a second step of pitch addition directly after the stirring step and prior to the firing step for the purpose of ensuring sufficient pitch coverage of the graphite (“carbon-based particle”) and silicon by the pitch. In the combination of Chang and Carel, the pitch in the second step of pitch addition would be a “second carbon precursor”.
Regarding 2), it is well-known in the art to use as active material silicon particles with a degree of crystallinity greater than 70% – see, e.g. Schulz (paragraph [0047]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to ensure that the crystallinity of the silicon particles after firing is greater than 70% for the purpose of optimizing the performance of the battery.
Regarding 3), the presence of an outermost carbon coating layer positioned on a composite layer including silicon particles dispersed in a carbon matrix is a known configuration in the art.
Jo teaches an analogous anode active material including a graphite core (117) and a composite coating layer positioned on the graphite core (117). Jo’s material is prepared in a manner analogous to Chang involving mixing silicon particles, graphite core and a polymer material as a carbon precursor and then firing (paragraph [0159]).
In Jo’s material, the composite coating layer includes an inner band formed of silicon particles (111) dispersed within a carbon layer matrix (115) (paragraphs [0112-0114, 0124] and figure 3). This inner band is equivalent to the instantly claimed “composite layer”.
The composite coating layer further has an outer band, which does not include the silicon particles (111) and only includes the carbon matrix material (115). This outer band of the composite coating layer is equivalent to the instantly claimed “outermost carbon coating layer” positioned on the “composite layer” (figure 3).
Jo teaches that the diameter of the crystalline carbon particle (117) may be in the range 300 nm to 30 µm (paragraph [0116]). Jo further teaches that the diameter of the full particle (100) may be 500 nm to 35 µm (paragraph [0120]).
It can thus be calculated that the combined thickness of the “composite layer” and the “outermost carbon coating layer” is in the range 100 nm to 2.5 µm.
The thickness of the “composite layer” is determined by the diameter of the silicon particles (figure 3). Jo teaches that the diameter of the silicon particles is in the range 20 nm to 200 nm (paragraph [0078]).
Then, the thickness of the “composite layer” is approximately in the range 20 nm to 200 nm and the thickness of the “outermost carbon coating layer” is in the range 80 nm to 2.3 µm.
The function of the carbon is to suppress the volume expansion of the silicon particles during charging and discharging (paragraph [0121]).
See, also Lee who teaches an anode active material including a graphite particle (1) and a composite coating layer positioned on the graphite particle (1). The composite coating layer includes an inner band formed of silicon particles (2) covered in a first carbon coating layer (3) and further covered by a second carbon coating layer (4) (paragraph [0041] and figure 1). The second carbon coating layer (4) has a thickness of 100 nm to 1.5 µm (paragraph [0060]). The purpose of the second carbon coating layer (4) is to control the volume change of the silicon upon charge and discharge and to maintain the shape of the particles (paragraph [0059]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to use Chang’s method to form an anode active material including the graphite (“carbon-based particle”), the “composite layer” positioned on the graphite (“carbon-based particle”) and including silicon particles dispersed in a carbon matrix and an “outermost carbon coating layer” positioned on the “composite layer” and having a thickness in the range 80 nm to 2.3 µm for the purpose of controlling the volume change of the silicon particles occurring during charge and discharge and thus maintaining the shape of the particles.
The optimum range for the thickness of the “outermost carbon coating layer” in Chang as modified by Jo and Lee overlaps the instant range of 200 nm to 1 µm. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 4, Chang teaches that the graphite (“carbon-based particle”) is present at 90 wt%, the silicon is present at 2 wt% and the pitch (“first carbon precursor”) is present at 8 wt%. Chang as modified by Carel teaches that an overall total pitch may be in the range 10 wt% to 50 wt% (paragraph [0027]).
The optimum range for the sum of silicon and “first carbon precursor” and “second carbon precursor” in Chang as modified by Carel overlaps the instant ranges of 5 wt% to 50 wt% and 5 wt% to 40 wt%, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 5, Chang teaches that the silicon is present at 2 wt% (paragraph [0074]).
Regarding claim 8, Chang teaches a heat-treatment (“firing step”).
Carel teaches that carbonization may occur at a temperature in the range 600°C to 1400°C (paragraph [0033]).
Chang fails to teach that the heat-treatment (“firing step”) is performed at a temperature in the range 600°C to 700°C.
Jo teaches that using amorphous silicon particles and controlling the firing temperature permits for controlling the crystallinity of the final material and thus improves the performance of the battery (paragraphs [0048, 0123]). Jo teaches that suitable carbonizing temperatures are in the range 500°C – 800°C (paragraph [0096]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to use a firing temperature in the range 600°C – 800°C for the purpose of being able to carefully control the crystallinity of the active material and thus improving the performance of the battery.
The optimum firing temperature range in Chang as modified by Carel and Jo overlaps the instant application's optimum range of 600°C – 700°C. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claims 9 and 10, Chang as modified by Schulz teaches that the silicon particles in the composite layer have a degree of crystallinity of greater than 70% (Schulz’s paragraph [0047]).
The optimum degree of crystallinity range of Chang as modified by Schulz overlaps the instant application's optimum ranges of 74.9% to 95% or less and 74.95 to less than 95%. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 11, in the combination of Chang, Jo and Lee the thickness of the “composite layer” is determined by the diameter of the silicon particles.
In Chang’s example, the silicon particles have a diameter of 300 nm (paragraph [0074]). The composite layer would then have a thickness of about 300 nm.
Response to Arguments
Applicant’s newly added limitations have been considered. However, after further search and consideration, the combination of the Chang, Carel, Ka and Jo and Chang, Carel, Schulz and Jo references has been provided, as recited above, to address the amended claims.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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LILIA V. NEDIALKOVA
Examiner
Art Unit 1724
/MIRIAM STAGG/Supervisory Patent Examiner, Art Unit 1724
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