# 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

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_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.
- [How Organic Diodes Make Light Using Special Molecules](https://patentbrief.org/patent/us/4356429/oled-organic-light-emitting-diode) — Eastman Kodak's 1982 patent on creating light-emitting diodes (OLEDs) using organic materials, specifically a layer of porphyrinic compounds to help inject electrical charges.
- [How Chemically Strengthened Glass Works](https://patentbrief.org/patent/us/3778335/gorilla-glass-chemically-strengthened) — A 1971 Corning patent describing a specific chemical recipe for glass that can be made incredibly tough by swapping small atoms in its surface for larger ones.
- [How Nichia Created the First Practical Blue LED Electrodes](https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride) — A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable.