# 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. - **Patent:** US 4357215 - **Original title:** Fast ion conductors - **Owner:** Individual - **Granted:** 1982 - **Status:** Public domain (expired) - **Times cited:** 41 - **Field:** consumer_electronics, energy, materials ## What it does 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. ## 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. ## 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. ## Real-world examples 1. Lithium cobalt oxide (LiCoO2) cathodes in smartphones 2. Rechargeable battery packs for electric vehicles 3. Portable power banks ## Why it matters 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. ## 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. **Full plain-English explainer:** https://patentbrief.org/patent/us/4357215/lithium-ion-cathode-goodenough **Original patent:** https://patents.google.com/patent/US4357215 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Lithium-Cobalt Battery Cathodes Were Invented](https://patentbrief.org/patent/us/4302518/lithium-ion-battery-cathode) — This 1981 patent details the chemistry behind the lithium-cobalt oxide cathodes that power almost every modern smartphone, laptop, and electric vehicle. - [Early Lithium-Ion Battery Design Using Chalcogenides](https://patentbrief.org/patent/us/4009052/rechargeable-lithium-battery) — This 1977 patent describes an early rechargeable battery design using lithium as one electrode and titanium disulfide as the other, a key step towards modern lithium-ion technology. - [Recycling Lithium-Ion Batteries to Make New Cathode Materials](https://patentbrief.org/patent/us/10522884/method-and-apparatus-for-recycling-lithium-ion-batteries) — This patent describes a method for recycling used lithium-ion batteries by dissolving their cathode materials, adjusting the metal ratios in a liquid, and then pulling out a custom mix of materials for new batteries without needing extreme heat. - [Improving Lithium Battery Life with a Built-in Lithium Source](https://patentbrief.org/patent/us/10593988/electrochemical-cell-for-lithium-based-batteries) — This patent describes a method for building rechargeable lithium-based batteries with a special extra lithium source electrode inside that helps the main battery parts work better and last longer by giving them an initial charge of lithium ions. - [Making Safer Battery Separators with Ceramic Coatings](https://patentbrief.org/patent/us/11094998/ceramic-coated-separators-for-lithium-containing-electrochemical-cells-and-metho) — This patent describes how to make a special ceramic coating for battery separators using specific lithium-containing materials and a precise drying process to improve the safety and performance of lithium-ion batteries.