How Lithium-Ion Battery Cathodes Are Made
A foundational 1982 method for creating the materials used in rechargeable lithium-ion batteries by removing ions at low temperatures.
Original patent title: “Fast ion conductors”
A foundational 1982 method for creating the materials used in rechargeable lithium-ion batteries by removing ions at low temperatures. Granted to Individual in 1982 with 4 claims and 41 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes a chemical process to create stable materials for battery electrodes, specifically those with a layered structure like alpha-NaCrO2. The inventors discovered that you cannot create these materials using high-heat methods because the structure becomes unstable. Instead, the patent claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → a method of electrochemical extraction, where you pull positive ions (like Lithium) out of a starting compound at low temperatures to create the final, active electrode material.
The gap
What does this patent NOT cover?
- Does not cover the physical assembly of a complete battery cell.
- Does not cover high-temperature manufacturing processes for these materials.
- Does not cover the use of materials that do not follow the specific A x M y O 2 layered structure.
- Does not cover the specific electrolyte compositions used in the battery.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The inventors realized that high-temperature synthesis destroyed the material's stability, so they used electrochemical extraction at low temperatures to 'strip' ions out, creating a stable, high-energy-density structure that shouldn't have existed otherwise.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Lithium cobalt oxide (LiCoO2) cathodes in smartphones
Rechargeable battery packs for electric vehicles
Portable power banks
Why it matters
The bigger picture
This patent is a cornerstone of modern portable electronics. It provided the chemical blueprint for the cathode materials found in almost every lithium-ion battery used in smartphones, laptops, and electric vehicles today. John B. Goodenough later received a Nobel Prize for this work, which enabled the transition from disposable batteries to rechargeable ones.
Filed
April 30, 1981
Granted
November 2, 1982
Market context
Who's building on this
Companies in this space
Major battery manufacturers like Panasonic, LG Energy Solution, and CATL build upon these fundamental material science principles. The technology is now industry-standard, and research continues into optimizing these layered oxides for higher energy density.
Market impact
This patent effectively enabled the entire lithium-ion battery industry. By defining a viable way to produce stable cathode materials, it allowed for the miniaturization of power sources, which directly led to the development of the modern mobile computing and electric vehicle markets.
Claim 1 — Plain English
What this patent covers
This patent describes a chemical process to create stable materials for battery electrodes, specifically those with a layered structure like alpha-NaCrO2. The inventors discovered that you cannot create these materials using high-heat methods because the structure becomes unstable. Instead, the patent claims a method of electrochemical extraction, where you pull positive ions (like Lithium) out of a starting compound at low temperatures to create the final, active electrode material.
The clever bit
The inventors realized that high-temperature synthesis destroyed the material's stability, so they used electrochemical extraction at low temperatures to 'strip' ions out, creating a stable, high-energy-density structure that shouldn't have existed otherwise.
What it does not cover
- Does not cover the physical assembly of a complete battery cell.
- Does not cover high-temperature manufacturing processes for these materials.
- Does not cover the use of materials that do not follow the specific A x M y O 2 layered structure.
- Does not cover the specific electrolyte compositions used in the battery.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
32/40
Moderately cited
Claim breadth
3/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$13K – $40K
Midpoint $25K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
4 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Mizushima, K., & Goodenough, J. B. (1982). How Lithium-Ion Battery Cathodes Are Made (U.S. Patent No. 4,357,215). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4357215/lithium-ion-cathode-goodenough
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Lithium-Ion Battery Cathodes Are Made cover?
A foundational 1982 method for creating the materials used in rechargeable lithium-ion batteries by removing ions at low temperatures.
Who owns patent US 4357215?
Individual owns this patent, granted in 1982.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 4357215 cited by?
This patent has been cited by 41 later patents that build on its ideas.
What problem does this patent solve?
This patent is a cornerstone of modern portable electronics. It provided the chemical blueprint for the cathode materials found in almost every lithium-ion battery used in smartphones, laptops, and electric vehicles today. John B. Goodenough later received a Nobel Prize for this work, which enabled the transition from disposable batteries to rechargeable ones.
What does this patent NOT cover?
Does not cover the physical assembly of a complete battery cell.
Same assignee
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