LG Energy Solution Ltd v. Molecular Rebar Design LLC

1. Case Identification

• Case #: IPR2024-01011
• Patent #: 8,968,924
• Filed: June 12, 2024
• Petitioner(s): LG Energy Solution, Ltd.
• Patent Owner(s): Molecular Rebar Design, LLC
• Challenged Claims: 1-5

2. Patent Overview

• Title: Lithium Ion Batteries Using Discrete Carbon Nanotubes, Methods for Production Thereof and Products Obtained Therefrom
• Brief Description: The ’924 patent discloses compositions for lithium-ion batteries that comprise discrete, oxidized carbon nanotubes (CNTs) with ion active materials attached to their surface. The claims specify ranges for nanotube aspect ratio, oxidation levels, and weight percentage relative to the ion active material.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4, and 5 are obvious over Ohata in view of Kavan

• Prior Art Relied Upon: Ohata (Application # 2004/0160156) and Kavan (a 2010 Journal of Power Sources article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Ohata disclosed most elements of the challenged claims, including a composition for lithium-ion batteries containing discrete CNTs with an ion active material. Ohata taught creating a masterbatch by blending CNTs with a resin to achieve good dispersion for an electrode paste. However, Ohata did not explicitly teach using oxidized CNTs. Kavan supplied this missing element, describing composites of functionalized (oxidized) multi-walled CNTs and electrode active materials (e.g., LiFePO₄) for use in lithium-ion batteries. Kavan specifically taught that oxidation improves the anchoring of active materials to the CNTs and discloses an atomic oxygen percentage of 7%, which Petitioner calculated to be a 9.1% oxidation level by weight, falling within the claimed range of 1-15%. Furthermore, Ohata disclosed CNT aspect ratios (e.g., 50, 100, 200) and weight percentages (e.g., 0.2% to 3.0%) that fall within or overlap the ranges recited in claims 1 and 4.
  • Motivation to Combine: A POSITA would combine Kavan’s teachings with Ohata’s process for several reasons. First, using Kavan's oxidized CNTs would improve the electrochemical performance of the electrode, a known benefit taught by Kavan. Second, oxidation enhances the dispersion of CNTs, which would have furthered Ohata’s stated goal of creating a well-dispersed nanotube paste. Third, oxidative treatments were a known method for purifying CNTs. The combination was merely the application of a known technique (using oxidized CNTs) to a known composition (Ohata’s electrode paste) to achieve predictable results.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because the use of oxidized CNTs in lithium-ion battery electrodes was conventional. The components and slurry compositions described in Ohata and Kavan were similar, suggesting their teachings were compatible.

Ground 2: Claims 1-5 are obvious over Cheng, Gan, and Zhao

• Prior Art Relied Upon: Cheng (Chinese Publication # 101714627), Gan (Application # 2012/0058255), and Zhao (Chinese Publication # 102136576).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Cheng taught a carbon nanotube/lithium iron phosphate composite material for battery cathodes, focusing on methods to achieve uniform dispersion of CNTs to form an effective conductive network. Gan taught that functionalizing (oxidizing) CNTs with carboxyl or hydroxyl groups within a specific range (about 2.5 to 10 wt%) improved dispersibility and reduced electrical contact resistance without degrading the CNTs' intrinsic properties. This oxidation level falls within the ’924 patent’s claimed range. For claims 2 and 3, Zhao taught adding sheet-like graphene to a fibrous CNT/carbon black composite to create a synergistic, multi-dimensional conductive network that improves battery performance. Zhao also disclosed a weight ratio of graphene to CNT composite that taught a graphene percentage (approx. 9 wt%) falling within the broad range claimed.
  • Motivation to Combine: A POSITA would have been motivated to modify Cheng’s composite by using the functionalized CNTs taught by Gan. This modification would directly address Cheng’s primary objective of improving CNT dispersion and forming a better conductive network. Gan provided specific guidance on an optimal oxidation level to achieve these benefits. A POSITA would have been further motivated to add graphene to the Cheng-Gan composite as taught by Zhao to further enhance electronic conductivity and performance through the creation of a synergistic, multi-dimensional conductive network.
  • Expectation of Success: A POSITA would have expected success because functionalizing CNTs to improve dispersion was a well-known technique, and Gan provided a predictable range for this functionalization. The benefits of combining different carbon allotropes like nanotubes and graphene, as taught by Zhao, were also well-understood for improving electrode conductivity. The combination involved applying known solutions to solve known problems in the field.

4. Key Technical Contentions (Beyond Claim Construction)

• Priority Date Challenge: Petitioner dedicated a significant portion of the petition to arguing that the ’924 patent was not entitled to its claimed priority date of June 23, 2011, from the ’560 provisional application. Petitioner contended that the ’560 application lacked written description support for key limitations first introduced later in a PCT application, specifically the aspect ratio range of "10 to 500" and the weight ratio of graphene to CNTs of "0.1:99.9 to 99.9:0.1." Therefore, Petitioner argued the correct critical date for the challenged claims is June 21, 2012, ensuring all asserted prior art references pre-date the invention.

5. Arguments Regarding Discretionary Denial

• Fintiv Factors: Petitioner argued that discretionary denial under Fintiv would be inappropriate. Key reasons included that the petition was filed diligently and early in a parallel district court proceeding, which has a trial date well after the statutory deadline for a Final Written Decision. Furthermore, Petitioner stipulated that it would not pursue the same invalidity grounds in the district court if an IPR is instituted.
• Advanced Bionics (§325(d)): Petitioner argued that denial under §325(d) was unwarranted because the petition raised new prior art and arguments. None of the primary references asserted in the grounds (Ohata, Kavan, Cheng, Gan, or Zhao) were previously cited or considered by the Examiner during the prosecution of the ’924 patent.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-5 of the ’924 patent as unpatentable.