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.

What it 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.

What it doesn't 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.

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.

Real-world examples

• 1.Lithium cobalt oxide (LiCoO2) cathodes in smartphones
• 2.Rechargeable battery packs for electric vehicles
• 3.Portable power banks