# 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. - [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. - [How to Fast-Charge Lithium Batteries Without Damaging Them](https://patentbrief.org/patent/us/10700376/methods-for-fast-charging-and-detecting-lithium-plating-in-lithium-ion-batteries) — This patent describes a three-phase method for quickly charging lithium-ion batteries while carefully controlling voltages to prevent harmful lithium metal buildup and electrolyte damage. - [Making Solid-State Battery Electrodes That Don't Swell and Crack](https://patentbrief.org/patent/us/11239459/low-expansion-composite-electrodes-for-all-solid-state-batteries) — This patent describes a special design for solid-state battery electrodes that uses tiny internal holes and spaces between particles to prevent them from expanding and cracking during charging and discharging.