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Preview – Lithium-ion Battery High Energy Anode Innovation & Patent Review

  • Executive Summary

  • This review discusses divergent technical decisions taken by key lithium-ion battery industry players to synthesize high energy negative electrode materials and corresponding electrodes for battery cells with liquid, semi-solid and solid electrolytes. The methodology used to prepare this review is based on a AI-supported analysis of global patent filings, enriched with information gained from news releases & participation at key battery conferences.

  • Replacement of Graphite with Higher Energy Materials

  • Graphite has been the negative electrode material of choice for Li-ion batteries for many years, but it exhibits a theoretical capacity limit of 372 mAh/g (cost estimate OneD Battery Sciences: about USD 6.85/kWh). For this reason, graphite has to be gradually and eventually fully replaced with higher energy materials if energy density is to be further increased.

  • Impact of New Semi-Solid & Solid Electrolytes on Negative Electrode Selection

  • Fervent development and commercialization efforts of semi-solid and solid electrolytes for Li-ion batteries (including in the EV space) might well supercharge the adoption of Si-rich negative electrodes (>1,000 mAh/g capacity) in mass applications over the next 5-10 years because of the prospect of substantial energy density gains (>1,000 Wh/L / >400 Wh/kg at cell level, which is expected to convert to about 20% higher range in EVs as compared to current negative electrodes) along with substantial potential electrode production cost savings (in terms of Wh/kg). In liquid electrolyte cells, graphite will probably remain the main active material component in mass applications alongside SiOX for the foreseeable future (X = 0.4-1, 5-12 mass%, electrode capacities up to about 650 mAh/g). For cost reasons, Si-rich negative electrodes (1,400-3,300 mAh/g capacity) in liquid electrolyte cells are being deployed mostly in niche applications (wearables, unmanned and manned air transport, soldier battery packs).

  • Key Product Definition Approaches to Si-based Anode Materials & Electrodes

    • SiOX microparticles (X ≈ 0.4-1, 1,300-1,900 mAh/g capacity, about 6 µm diameter), which are already used as capacity-boosting additives (5-10 mass% with liquid electrolytes, ≥14 mass% with semi-solid electrolytes) in combination with graphite to manufacture negative electrodes with up to 650 mAh/g capacity (with liquid electrolytes) for electronics and EV applications (cycling for several thousand cycles). Advantage: favorable compensation of volume changes / cycling stability; Potential disadvantage: side reactions caused by silicon dioxide limit achievable energy density. Key players: BTR (China), Daejoo Electronic Materials (Korea), Shanshan (China), Shin-Etsu (Japan).

    • Sphere-like Si-carbon core-shell microparticles with 1,400-2,200 mAh/g capacity in which high surface area nanoscale Si, carbon (e.g. graphene) & void volume are protected from liquid electrolyte access by a carbon shell (for liquid electrolyte cells, carbon shell is optional for semi-solid and solid electrolyte cells). Commercial deployment was achieved in 2021 for wearable applications (Sila Nanotechnologies, liquid electrolyte cells). Advantage: high cycling stability at high energy density. Potential disadvantage: costs. Key players: Samsung (Korea), Sila Nanotechnologies (USA). Related approach - Laser-carbonized Si-carbon electrodes: Enevate (USA).

    • Si nanowires and other nanostructures with up to 3,300 mAh/g capacity formed through chemical vapor deposition (CVD) of monosilane gas, either on carbon powders (attractive costs) or on metal current collector foils (very high energy density), used already in niche aerospace and defense applications. Advantage: excellent control of nano-architecture allows for very high energy density, including potentially in the context of dry electrode manufacturing processes pursed by Tesla (for Si on carbon powders). Potential disadvantage: sufficient cycling stability for EV & stationary applications is to be demonstrated. Key players: Si on carbon powders: Group14 Technologies (USA), Nexeon (UK), OneD Battery Sciences (USA, cost target: USD 3.25 for Si-carbon composite, USD 1.67/kWh for Si component), Resonac (Japan); Si on electrodes: Amprius (USA/China, electrodes), LeydenJar (Netherlands, electrodes).

    • Si microparticles (in some cases with carefully designed nanoporosity or Li-ion conductive polymer coatings) with up to 3,300 mAh/g capacity , formed for example through milling of low cost Si precursors. Advantage: very attractive costs that - in case of sufficient performance - would commoditize anode materials industry. Potential disadvantage: whether or not sufficient cycling stability with semi-solid or solid-state cells for EV & stationary applications will be reached is less clear than with the other approaches (the chance of reaching sufficient cycling stability with liquid electrolytes is low). Key players (cell / EV producers): LG Energy Solution (Korea), Tesla (USA, cost target: USD 1.2/kWh, cost of sufficiently pure metallurgical Si precursor according to E-magy: about USD 3.5-4.5/kg, corresponds to USD 0.25-0.32/kWh), Toyota (Japan).

  • Introduction

  • Focus of this Review

  • This review discusses divergent technical decisions taken by key lithium-ion battery industry players to synthesize high energy negative electrode materials and corresponding electrodes for battery cells with liquid, semi-solid and solid electrolytes, based on a AI-supported analysis of global patent filings, enriched with information gained from news releases & participation at key battery conferences.

    The review supports the Li-ion battery community in understanding the different technical avenues that have been evaluated (decision trees). Comprehension of the high energy negative electrode state-of-the-art allows for the identification of promising product development & commercialization directions that have not yet been explored.

    Patents by key players are classified according to these categories: A) chemical composition; B) particle nano- & microarchitectures, composites; C) surfaces & coatings; D) large scale manufacturing, reliability; E) negative electrode formulations (for liquid electrolytes); F) active materials for solid-state or semi-solid Li-ion batteries.

    New sections as compared to the review from October 2020 are labeled in red, either at the level of individual patents or image sections, or at the level of red-labeled titles if a whole section was newly introduced or replaced.

    For tailored patent searches, the AI models used for preparation of this review are available to users on b-science.net (scoring of commercial relevance).

  • Li-ion Battery Cell Components

  • The different components of a Li-ion battery cell are shown in Figure 1 below. Each battery cell contains a negative electrode or anode, a positive electrode or cathode, and a Li-ion conducting, electrically isolating region that separates these two electrodes, which consists of a porous separator soaked with liquid, Li-ion conducting electrolyte, or alternatively of a solid electrolyte layer.

    Negative electrodes consist of a current collector (usually based on copper) that is coated with an active material layer made of anode active material particles, (in most cases) electrically conductive carbon additives and a binder (in some cases carbonized) .

    Figure 1: Li-ion battery cell components

    Li-ion battery cell components

    An interesting approach pursued by multiple companies according to patent filings is the deployment of solid electrolyte matrices in the negative & positive electrodes that prevent contact between the liquid electrolyte and the electrode active materials (prevention of excessive reactivity, especially at elevated temperatures), while a liquid electrolyte-filled separator can still assure favorable Li-ion conductivity between the electrodes.

  • Technology Decision Trees for High Energy Negative Electrodes

  • The technology decision trees below should not be regarded as comprehensive as only recently published patent families are covered for the most part, but hopefully as a source of inspiration for novel inventions and for the identification of technical approaches that have been ‘under-explored’ thus far. Additions / changes as compared to the 2020 review edition are shown in red. Prior reviews from 2020 and 2019 can be consulted for a wider publication time frame.

    Figure 10: decision tree - nano-Si (synthetic processes)

    Lithium-ion battery technology decision tree – decision tree - nano-Si (synthetic processes)
    Proponents of CVD bottom-up Si nanostructure synthesis approaches (Figure 10: on current collector foils or particle deposition, Amprius, ATL, Cenate, LeydenJar, OneD Battery Sciences, Wacker Chemie; Figure 11: on carbon support materials, Group14 Technologies, Livenergy, Nexeon, OneD Battery Sciences, Resonac, Sila Nanotechnologies, SK Innovation) argue that to achieve higher energy densities, process technology transfer from high value added industries (semiconductors, flat panel displays, solar cells) to the battery industry is necessary to better control nanoscale structures as compared to current processes. While hazardous monosilane is already employed in the range of 10,000-100,000 tons/year in other industries, its large scale use requires tighter safety procedures as compared to many of the currently used large scale battery material manufacturing processes. A wide variety of nano-architectures can be achieved with this approach that are not accessible with other synthetic approaches, which is aided by the choice of catalysts and carbon or silicide support materials on which Si is deposited. Highly attractive process costs of around USD 19.7/kg Si (USD 1.67/kWh) have been claimed by OneD Battery Sciences to be feasible at large scale, which drive evaluation efforts in the context of EV applications (not only niche applications).

    It is a new development that dry ball milling approaches (Figure 10, Daejoo Electronic Materials, Panasonic, Samsung, Wacker Chemie) are pursued to a similar extent as wet milling approaches (Amprius, BTR, Paraclete, Posco, Samsung, Shanshan, StoreDot, Wacker Chemie, use of a variety of solvents and polymer additives). Because the use of solvents and solvent recycling can be skipped with dry ball milling approaches, they can be assumed to generally exhibit lower process costs as compared to wet milling processes. In general, the uniformity of the products (e.g. narrowness of particle size distribution) cannot be controlled to the same extent with milling approaches as compared to bottom-up silane gas deposition processes, but the precursor material is frequently comparably low cost Si powder (raw material cost estimate by Dr. Axel Schonecker from E-magy at a discussion panel during Battery Show Europe 2021: USD 3.5-4.5/kg - this price level is predominantly determined by the level of Si purity).

  • AI-based Identification of Commercially Relevant Patents

  • b-science.net has developed a supervised AI methodology to assess the commercial relevance of patents, combined with an automatic translation framework that makes sure Non-English patents are identified. The methodology was validated as shown below. With this approach, we have comprehensively identified & classified patents by companies active in commercial R&D on Li-ion battery negative electrodes.

    In Table 2, the number of commercially relevant negative electrode patent families published since 2017 are listed for 447 companies (excluding lithium metal negative electrodes).

    Table 3 contains patent filings that relate to negative electrodes (without lithium metal electrodes) and semi-solid or solid electrolytes, as identified with the help of two corresponding AI models.

    Table 2: number of commercially relevant Li-ion battery anode patent families / utility models between January 2017 and November 18th, 2021 (publication of first family member, excluding lithium metal negative electrodes)
    SSB: patent filings that relate to solid-state or semi-solid Li-ion batteries
    Grape: battery suppliers / developers and automotive suppliers
    Blue: anode material suppliers
    Black: companies that are not discussed in detail (in a few cases, a single patent is discussed)

    Number of commercially relevant patent families / utility models since 2019 in the category solid-state / semi-solid Li-ion batteries
    Table 3: number of commercially relevant / utility models that relate to both Li-ion negative electrodes (without lithium metal anodes) and semi-solid or solid electrolytes, between January 2018 and November 18th, 2021 (publication of first family member)
    Grape: battery suppliers / developers and automotive suppliers
    Blue: anode material suppliers
    SSB Chapter: company chapter in ‘Solid-State Li-Ion Battery Innovation & Patent Review’

    Number of commercially relevant patent families / utility models since 2019 in the category solid-state / semi-solid Li-ion batteries

  • Anode Material Suppliers

  • In the following chapters, patent families for which the earliest family member was published after July 24th, 2020 (cutoff date of prior review) are highlighted in red color (a limited number of earlier patents are also highlighted in red, if they were not included in the prior review).

    In maroon color, it is described why - in the author’s opinion - a patent filing could potentially contain a commercially relevant invention, or why it exhibits a limitation.

  • Resonac - Japan (links to data sources are included in the full version)

  • Organization Profile

    Resonac (http://www.resonac.com, former name: Showa Denko) is the manufacturer of SCMG artificial graphite active materials, VGCF (vapor grown carbon fiber) conductive additives for the positive and negative electrode, carbon-coated current collector foils, and packaging materials for Li-ion batteries.

    In 2019, Showa Denko completed the takeover of its bigger rival Hitachi Chemical, in which the Hitachi Group formerly held a majority stake and subsequently renamed to Resonac. In 2019, Showa Denko made an investment in Group14 Technologies. The former Hitachi Chemical division of Resonac is a long-standing, market-leading supplier of anode materials and of other materials used in Li-ion batteries. A speciality is artificial graphite with carefully tuned pore size distribution for favorable Li-ion diffusion. In 2018, Showa Denko Materials licensed silicon-based electrolyte technology from US-startup Silatronix to improve electrochemical performance of its anode materials. In 2018, an investment was made in Massachusetts-based startup company Ionic Materials.

    Unique capability (former Hitachi Chemical division): manufacturing of SiOX (0.5 ≤ X ≤ 1) at various performance / cost points (i.e. high performance materials at comparably high costs - presumably through SiO gas deposition, lower performance materials at comparably low costs - presumably through SiO milling).

    Leap of faith (former Showa Denko division): fast-follower approach in the area of silane coating of carbon will lead to competitive market position.

    Possible composition of future negative electrode materials

    Former Hitachi Chemical division (liquid electrolyte cells)

    • SiOX (0.5 ≤ X ≤ 1), with highly crystalline SiO2 domains for limited irreversible losses.
    • coated with carbon and optionally with a polymer (artificial SEI).
    • incorporation of LiF.
    • mixed with artificial graphite and flaky graphite.

    Former Showa Denko division (semi-solid or solid electrolyte cells)

    • Si-coated activated carbon.
    • possibly CVD-coated with a carbon layer.
    • possibly mixed with artificial graphite and flaky graphite.

    Test electrode composition

    Former Hitachi Chemical division

    • carbon additives: artificial graphite (in-house), Ketjen black (Lion Specialty Chemicals Co., Ltd.), acetylene black (HS-100, Denka), flaky graphite (KS6, IMERYS Graphite & Carbon), carbon black (Super C45, IMERYS Graphite & Carbon).
    • binder: CMC/SBR, PAA, PAN, or polyamideimide.

    Former Showa Denko division

    • carbon additives: VGCF (Resonac), carbon black (IMERYS Graphite & Carbon).
    • binder: SBR/CMC.

    Figure 25: projected manufacturing process option for Resonac (formerly Hitachi Chemical)

    Li-ion battery anode active material – projected manufacturing process option for Resonac (formerly Hitachi Chemical)

    Figure 26: projected manufacturing process option for Resonac (formerly Showa Denko)

    Li-ion battery anode active material – projected manufacturing process option for Resonac (formerly Showa Denko)

    News reports and press releases

    No news articles were identified in relation to Resonac’s anode materials. The collaboration with Umicore might not have been continued after the takeover of Hitachi Chemical (latest publication of joint patent family by Umicore and Showa Denko in 2019).

    Earlier technical information that remains relevant

    The process projection in Figure 25 for Resonac (formerly Hitachi Chemical) retains important steps from the prior review. Consequently, earlier patent families listed below on SiO gas quenching, carbon CVD or coal tar pitch coating and polymer coating probably remain very important.

    Recently Published Patent Filings

    As shown in process Figure 25, recently published patent filings suggest that Resonac (formerly Hitachi Chemical) focuses on process (and likely cost) optimization while maintaining performance characteristics in SiOX (0.5 ≤ X ≤ 1) materials (key steps: high impact milling to tune Si & SiO2 domain sizes and crystallinity, incorporation of LiF).

    While the incorporation of LiF into SiOX is in focus, the incorporation of LiCl and Al6Si2O13 was also investigated. Resonac (formerly Showa Denko) made a pivot in its patent filings from with Si nanoparticles and pitch (in collaboration with Umicore) to a new focus on monosilane CVD coating of activated carbon (process Figure 26), which is being pursued already by other companies (see Figure 11).

    Resonac (formerly Showa Denko) also started efforts towards developing Si-containing active materials that can be combined with sulfide solid electrolytes.

    General patent portfolio characteristics

    Among battery materials manufacturers, Resonac holds the 2nd largest number of newly published patent families related to Li-ion battery anodes since 2018 (117) behind Shanshan. 8 of these patent families are also related to solid-state or semi-solid electrolytes. Showa Denko made joint filings with Umicore (latest patent family published in 2019) and Nohms Technologies (2 patent filings published in 2021, related to liquid electrolytes for graphite electrodes, example: EPO).

    Examples from the patent portfolio - Resonac (formerly Hitachi Chemical)

    A) Chemical composition

    Figure 27: X-ray diffraction measurement of SiOX (X ≈ 1) material with highly crystalline SiO2 domains (Resonac, formerly Hitachi Chemical)
    X-ray diffraction measurement of SiOX (X ≈ 1) material with highly crystalline SiO2 domains (Resonac, formerly Hitachi Chemical)

    B) Particle nano- & microarchitectures, composites
    C) Surfaces & coatings
    D) Large scale manufacturing, reliability
    E) Negative electrode formulations (for liquid electrolytes)

    Examples from the patent portfolio - Resonac (formerly Showa Denko)

    B) Particle nano- & microarchitectures, composites
    • Process in Figure 26: Carbon-coated composites and their uses  (2021, covered in patent update): activated carbon (BET SSA: 900 m2/g) was treated with silane gas in a tube furnace (1.3 volume% in nitrogen, 500 °C, 760 torr, 6 h). The resulting composite particles exhibit a silicon content of 45 mass% and a BET specific surface area of 16.9 m2/g. The material exhibits a reversible capacity of 1,800 mAh/g and a first cycle efficiency of 91.2%. Electrolyte: EC / EMC / DEC = 3 : 5: 2 by volume, additives: VC (1 mass%), FEC (10 mass%). In full cells with LCO-based positive electrodes, 60% capacity retention was observed after 50 cycles.
      While a favorable 1st cycle efficiency was obtained, further work appears to be necessary to improve cycling stability in full cells.
    • TITANIUM OXIDE-SILICON COMPOSITE AND USE OF SAME  (2021, covered in patent update): TiO2 was exposed to a He atmosphere, followed by treatment with silane gas (400 °C), followed by purging with He gas. An SEM-EDX analysis exhibits that Si was incorporated between TiO2 domains. Negative electrode formulation: Ti-Si-O material, graphite, VGCF (Resonac), carbon black, CMC (CMC1300 from Daicel), SBR (10.1 : 79.9 : 3 : 2 : 2.5 : 2.5 by mass). In half cells, a discharge capacity of 494 mAh/g was observed and a 1st cycle efficiency of 89.3%.
      This work could allow for negative electrode active materials with favorable longevity, if the material exhibits reduced parasitic reactivity as compared to SiOX (X ≈ 1).
    C) Surfaces & coatings
    F) Negative electrode active materials & formulations for solid-state or semi-solid Li-ion batteries
    • COMPOSITE MATERIAL, MANUFACTURING METHOD THEREFOR, NEGATIVE ELECTRODE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND THE LIKE  (2021, covered in patent update): this patent describes efforts towards making titanium oxide coated anode materials that can be used in combination with sulfide solid electrolytes. SCMG artificial graphite and an Si-carbon material were combined with titanium oxide and dry-mixed (VM-10 mixer, Dalton Corp.), followed by a heat treatment (1,100 °C with SCMG precursor, 700 °C with Si-carbon precursor, 1 h, nitrogen atmosphere). This material was further treated with an MP-01 mini (Paulec Co.) apparatus to obtain a titanium oxide coating, followed by another heat treatment (400 °C, air, ≤25% humidity). The coating leads to improved cycling stability.
      This work illustrates how Resonac employs a titanium oxide coating to graphite and Si-carbon materials to improve longevity in cells with sulfide solid electrolytes.
    • ALL-SOLID LITHIUM ION BATTERY NEGATIVE ELECTRODE MIXTURE AND ALL-SOLID LITHIUM ION BATTERY  (2020): Si particles (50 nm average diameter, 51.5 m2/g BET SSA) and petroleum pitch (10 : 11.54 mass ratio) were mixed at 250 °C at high shear rate under inert gas, followed by a heat treatment (up to 1,100 °C, under nitrogen). With the resulting material, negative electrodes were prepared in combination with 3 mass% Super C45 carbon black (IMERYS Graphite & Carbon) and 3 mass% polyacrylate binder. Solid-state battery cells were prepared with Li2S ∙ P2S5 and an LCO-based positive electrodes.
      This work illustrates how Resonac is optimizing its negative electrode active materials for use with sulfide electrolytes.

  • Table of Contents (237 pages, see PDF)

    • Focus of This Review
    • Li-ion Battery Cell Components
    • Replacement of Graphite with Higher Energy Materials
    • Impact of New Semi-Solid & Solid Electrolytes on Negative Electrode Selection
    • Chemical Composition (Core)
    • SiOX (X ≈ 1) (Synthetic Processes)
    • Incorporation of Lithium into SiOX (X ≈ 1)
    • Incorporation of Heteroelements into SiOX (X ≈ 1)
    • SiOX (X ≈ 1) (Coatings)
    • Functionalization of Carbon-Coated SiOX (X ≈ 1)
    • SiOX (X ≈ 1) Composites
    • SiOXC
    • Nano-Si (Synthetic Processes)
    • Coating of Carbon with Si
    • Nano-Si (Coatings)
    • Sphere-like Si-carbon or Si-MXene Composites Based on Solid Si Precursors (Synthetic Processes - Core)
    • Sphere-like Si-carbon or Si-MXene Composites Based on Solid Si Precursors (Non-Si Precursors)
    • Sphere-like Si-carbon or Si-MXene Composites Based on Solid Si Precursors (Binders / Dispersants)
    • Sphere-like Si-carbon or Si-MXene Composites Based on Solid Si Precursors (Coatings)
    • Si Alloys / Melts (Elemental Compositions / Coatings)
    • Additives for Negative Electrodes
    • Binders for Negative Electrodes
    • High Energy Electrode Designs & Fabrication Methods
    • Prospective Future Electrolyte Types for Negative Electrode Materials by Companies Discussed in this Review (Liquid, Semi-solid or Solid)
    • Negative Electrode Materials that are Used with Solid or Semi-solid Electrolytes
    • Predictions (5-10 Year Time Frame)
    • AI-Based Identification of Commercially Relevant Patents
    • Anode Material Suppliers
    • Advano (Nanostar) - USA
    • BTR / Beiterui - China
    • Daejoo Electronic Materials - Korea
    • Elkem / Vianode - Norway
    • Global Graphene Group / Nanotek Instruments - USA
    • Group14 Technologies - USA
    • Kaijin - China
    • LeydenJar Technologies - Netherlands
    • Nanograf / JNC - USA / Japan
    • Nexeon - United Kingdom
    • OneD Battery Sciences - USA
    • Paraclete (Kratos) - USA
    • Posco - Korea
    • Resonac - Japan
    • Shanshan - China
    • Shin-Etsu - Japan
    • Shinzoom - China
    • Sila Nanotechnologies - USA
    • Umicore - Belgium
    • Wacker Chemie - Germany
    • XFH - China
    • Zichen - China
    • Lithium-ion Battery Cell or Negative Electrode Suppliers, EV Producers
    • Amprius - USA / China
    • BYD - China
    • Contemporary Amperex Technology Limited (CATL) - China
    • Enevate - USA
    • Enovix - USA
    • LG Energy Solution / LG Chemical - Korea
    • Nanoramic - USA
    • Panasonic / Sanyo Electric - Japan
    • Samsung - Korea
    • StoreDot - Israel
    • TDK / Amperex Technology Limited (ATL) - Japan / China
    • Tesla / Maxwell Technologies / SilLion - USA
    • Toyota - Japan
    • Patents by Other Companies Covered in Patent Updates
    • Deep Dive - Silicon-based Negative Electrodes for Solid-state and Semi-solid Li-ion Batteries
    • Background Information
    • Introduction
    • Approaches Pursued by Key Players
    • A Semi-solid Cell Design That Might Permit for Favorable Process Costs Based on Limited Capital Expenditures (Drop-in Approach)
    • Disclaimer
    • Announced Efforts That Might Become Visible in the Patent Literature in the Future
    • Under-explored Product Development Approaches
    • Addendum: is Pre-lithiation Necessary or Can it Be Avoided?
    • The Importance of a Pragmatic Product Development Methodology

  • About the Author

  • Pirmin Ulmann obtained a diploma in chemistry from ETH Zurich (Switzerland) in 2004 and a PhD from Northwestern University (USA) in 2009. Thereafter, he was a JSPS Foreign Fellow in an ERATO academic-industrial project at the University of Tokyo (Japan). From 2010 to 2016, while working at a major battery materials manufacturer in Switzerland, he was a co-inventor of 7 patent families related to lithium-ion batteries. He was also in charge of a collaboration with the Paul Scherrer Institute, evaluated outside technologies for corporate strategy, and made customer visits to battery manufacturers in East Asia, North America & Europe. He holds the credential Stanford Certified Project Manager (SCPM) and has co-authored scientific articles with more than 1,800 citations.

  • Patent Analysis Methodology & Validation

  • The patent information source for this review is the European Patent Office (EPO), which covers patent filings from more than 100 patent offices around the world >2.2 Mio. patent documents are included in the b-science.net database that were published since 1980, which either contain the words 'battery' or 'batteries' in the title or abstract, or were assigned to one of the energy storage-related CPC (cooperative patent classification) or IPC (international patent classification) codes: H01M (batteries & fuel cells) or H01G (capacitors). In this review, patent families published between January 1st, 2017 and November 11th, 2021 were studied (publication date of earliest patent family member). Patent families that were not available in English in the EPO database were Google machine translated (titles, abstracts, applicants). Some Google translations of applicants were manually corrected. An AI model was defined for commercially relevant negative electrodes of Li-ion batteries (without Li metal electrodes). Patent documents were grouped into patent families and scored with the corresponding AI model. An AI relevancy score cutoff value of 40 was applied (100: very relevant, 0: not relevant). For companies listed in Table 2, scores between 35 and 45 were checked manually and false-positives / false-negatives were corrected if necessary. To generate Table 3, the AI model for solid / semi-solid Li-ion battery electrolytes was employed in combination with the AI model for Li-ion battery anode materials (without Li metal electrodes) to identify patent families with a connection to both of these categories. Only private / commercial companies are included in the statistic.
  • The methodology was validated with patent families filed in 2020 and 2021 by Posco. 20 patent families by Posco were manually classified as relevant. All of these patent families exhibit an AI score of ≥40 (higher than cutoff value). 1 patent with an AI score of 44 was manually classified as not relevant (false-positive, lithium metal electrode). 60 additional patent families by Posco were manually classified as not relevant and exhibit an AI score of <40 (lower than cutoff value).