DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
Status of Claims
Claims 1-15 are pending.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-15 are rejected under pre-AIA 35 U.S.C. 103 as being unpatentable over Ma et al (WO 2022/178798 A1 – wherein US 2024/0140808 A1 is used as the English language equivalent) in view of Oh et al (US 20220077467 A1), and further in view of Lee et al (US 20220271289 A1)
Regarding Claim 1,
Ma teaches a porous negative electrode active material comprising silicon elements such as SiOx (0<x<2) (Paragraph 0029), and a Mg compound or Lithium compound such as MgO, MgSO3, Li2SiO3 (Paragraph 0027). The negative electrode active material comprises a first structure made of silicon elements and the metal doping elements which are the Mg and Li compounds above (Paragraph 0006; silicon containing particles). The method of making the first structure per Ma will form a composite of the silicon and Mg or Li compound. Furthermore, Ma teaches a second structure coated on the surface of the first structure (Paragraph 0032), and the second structure comprises carbon (Paragraph 0033; carbon layer). Ma teaches that the specific surface area of the porous negative electrode active material is 2 to 15 m2/g (Paragraph 0031). This range is akin to that recited in claim 1.
Ma teaches that the invention uses the second structure in order to improve the conductivity of the porous negative electrode active material but does not specifically teach that the conductivity is 0.05 to 1 S/cm at a powder density of 1.4 g/cc. Ma also does not explicitly teach that the first structure has a specific surface area of 5 to 60 m2/g. The examiner contends, however, that these properties would be expected in the material of Ma as the 1) method of making the electrode material, 2) structure and 3) composition are equivalent to that of applicant’s material/process/structure.
Turning to applicant’s specification, examiner notes that the specification states that the silicon composite particle is made by vaporizing the Si powder and Mg/Li precursor (500-1200 C, 1000-1800 C), and then heat treating at 500-1000 C. Then cooling the particles at a rate of 2 – 60 C/min. The heat treatment and cooling steps controls the BET specific surface area of the silicon composite particle. The conductivity of the negative electrode active material is improved by presence of carbon layer on atleast a part of the surface of the silicon based particles, and even within the pores of the silicon based particles (per instant specification). The carbon layer is formed by using CVD method with a hydrocarbon or carbon source in a furnace at 600-1200 C while flowing argon gas.
Similarly, Ma teaches in terms of the method, that 1) the silicon based particles are formed by heating the silicon and 2) doping elements in a mixture, and cooling the mixture to room temperature at a cooling rate of not less than 20 C/min in order to form a porous structure (Paragraph 0039). Ma teaches that the first temperature to which the mixture is heated is (in some embodiments) 1000-1400 C. Ma also teaches that the carbon coating layer is formed by decomposing carbon source in a non-oxidizing atmosphere, and then subjecting pulverized silicon composite particle to a deposition coating reaction to form a carbon coating on the silicon based particle (Paragraph 0041). This process along with the parameters and temperature range(s) are similar to that described in the instant specification and thus, the examiner contends that Ma’s electrode active material will exhibit the same properties of specific surface area and conductivity. See MPEP 2112.01; when the structure recited in the reference is substantially identical to that of the claims, claimed properties are presumed to be inherent.
In addition, to reinforce the examiner’s conclusion, the references of Lee and Oh are further cited which do have similar methods/processes/composition to that of Ma and the instant specification and both appreciate the conductivity and surface area, respectively.
Lee teaches a negative electrode active material with a silicon oxide composite (SiOx and magnesium silicate), and a carbon film shell such that the conductivity of this material is 0.5 to 10 S/cm. Lee teaches that the silicon-carbon composite has a compressed density of 0.5 to 2 g/cc (Paragraph 0102). These properties of the negative electrode active material overlap with the claimed ranges. Lee also shows similarity in the method of making this negative electrode active material; the mixture of silicon and magnesium is heated at a temperature of 500-1600 C (Paragraph 0111), followed by cooling, pulverizing, and then forming a carbon coating process by a gas phase reaction at 600-1200 C (Paragraph 0113-0118) in inert gas such as argon, nitrogen (Paragraph 0130-0132). Lee also shows overlap between the composition, method of making and structure with the claimed invention. Hence, the examiner asserts that the conductivity as claimed would be expected in the material of Ma per the teachings of Lee.
With regards to specific surface area of the silicon containing composite particles, examiner notes that Ma does not teach that the area is 5 to 60 m2/g. However, Oh teaches a silicon-silicon oxide-magnesium silicate composite (Paragraph 0011), that has a coating layer of carbonaceous material (Paragraph 0044, 0045) that is used as negative electrode active material. Oh teaches that the silicon-silicon oxide-magnesium silicate composite particles have a BET specific surface area of 1-50 m2/g (Paragraph 0043). This range overlaps with the claimed range of 5 to 60 m2/g. Oh also shows similarity in the method of making the negative electrode active material; the silicon dioxide powder and Mg powder is heating at 1000-1800 C (Paragraph 0047), and the carbon deposition occurs at 600-1200 C through a CVD process (Paragraph 0051-0052). Hence, the examiner concludes that the specific surface area would be exhibited in the material of Ma per the teachings of Oh.
Therefore, the examiner contends that because Ma has overlapping and equivalent structure, composition and method of making the negative electrode active material, the surface area and conductivity would be expected. Furthermore, as noted in Oh and Lee, which mention the surface area and conductivity, the examiner further contends that the property would be expected to be present in the product of Ma.
Regarding Claim 2,
Ma does not specifically teach that the BET specific surface area of silicon containing composite particles is 20 to 60 m2/g, but based on the reasoning in above rejection the property is inherent to the material in Ma.
Furthermore, Oh teaches that the silicon-silicon oxide-magnesium silicate composite particles have a BET specific surface area of 1-50 m2/g (Paragraph 0043). This range overlaps with the claimed range of 5 to 60 m2/g. Thus, because Oh teaches equivalent methods to that of Ma and the instant specification, examiner contends that per Oh, the specific surface area would be expected in the active material of Lee.
Regarding Claim 3,
Ma teaches that the specific surface area of the porous negative electrode active material is 2 to 15 m2/g (Paragraph 0031). This range includes the claimed range. The active material has a high specific area because of its porous structure. Hence, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to have the active material with relevant specific area values in order to define the porous structure, and in turn improve cycle performance, and cycle stability (Paragraph 0030).
Regarding Claim 4,
Ma does not teach that the active material has conductivity of 0.05 to 0.8 S/cm, but based on the reasoning in above rejection of Claim 1 the property is inherent to the material in Ma.
Furthermore, Lee teaches the conductivity of the active material is 0.5 to 10 S/cm. The range of 0.5 to 0.8 S/cm overlaps with the claimed range. Hence, per the overlap in the teachings of Ma and Lee, the examiner contends that the conductivity would be expected in the electrode active material of Ma.
Regarding Claim 5 and Claim 6,
Ma teaches that the first structure (silicon composite) is a porous structure, and has micropores with a pore diameter of 2 nm -50 nm (Paragraph 0006). This range includes the claimed range of 2-45 nm. Hence, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to choose the relevant pore diameter from Ma in order to have more diffusion channels in order to alleviate cycle performance attenuation caused by volume expansion (Paragraph 0030).
Regarding Claim 7,
Ma teaches that the doping elements which are the magnesium and lithium salts (Paragraph 0027), are in the mass percentage of 1-15% (Paragraph 0028) to have better pore structure characteristics. This range is within the claimed range.
Regarding Claim 8 and Claim 9,
Ma teaches the metal doping elements can be salts such as MgO (oxide) or form silicates such as MgSiO3, Li2SiO3 (Paragraph 0027).
Regarding Claim 10,
Ma teaches the presence of the carbon layer on the surface of the silicon composite particle, and defines the thickness of the layer, but does not specifically define that the carbon layer is present in an amount of 1-50 wt% based on total active material.
However, Lee teaches that the content of carbon is between 2 wt% to 20 wt % based on the total weight of the silicon composite (Paragraph 0093). Hence, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to use the relevant weight % for carbon in the active material in order to maintain the increased conductivity, and not decrease the discharge capacity of the secondary battery (Paragraph 0094).
Regarding Claim 11 and Claim 12,
Ma teaches a method for preparing the porous negative electrode active material by preparing the silicon-containing composite described in steps S1 and S2 (Paragraphs 0036-0039), and then forming a coating of amorphous carbon or graphitized carbon (Paragraph 0040). Ma also teaches that the in the method of preparing the silicon composite or first structure, the cooling rate should be controlled to be above 20 ˚C/min. This overlaps with the claimed range of 2 to 60 ˚C/min. Hence, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to choose the relevant temperature rate of cooling in order to form the porous structure of the first composite structure (Paragraph 0039).
Regarding Claims 13-15,
Ma teaches that the negative electrode active materials prepared in the examples were mixed with conductive carbon black, and other components to form the electrode (Paragraph 0066), and the materials were applied to a button battery system (Paragraph 0066). This is akin to the claimed limitations of having a negative electrode with the active material, and further comprising carbon material that is then utilized in a secondary battery.
References of Interest
Park et al (US 20240266509 A1)
Park et al (US 20240063371 A1)
Oh et al (US 20230335715 A1)
Lee et al (US 20220384781 A1)
Lim et al (US 20220302428 A1)
Shin et al (US 20200168891 A1)
Kim et al (US 20180151874 A1)
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SUHANI JITENDRA PATEL whose telephone number is (571)272-6278. The examiner can normally be reached Monday-Friday 8:00 AM - 5:00 PM.
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/SUHANI JITENDRA PATEL/Examiner, Art Unit 1783
/MARIA V EWALD/ Supervisory Patent Examiner, Art Unit 1783