You can freely build on How Lithium-Cobalt Battery Cathodes Were Invented

What this patent covers

The patent describes a method for creating a specific type of battery electrode material using a layered atomic structure known as alpha-NaCrO2. By using electrochemical extraction, the inventors removed lithium ions from the material at low temperatures, which was previously impossible using high-heat manufacturing methods. This creates a stable, rechargeable structure where lithium ions can move in and out of the cathode, allowing the battery to store and release energy efficiently. It specifically identifies lithium-cobalt and lithium-nickel oxides as the active materials for these cathodes.

What is now free to use

All 1 claims of US 4302518 are in the public domain. Specifically:

The 1 dependent claim add narrowing limitations and are also free.

What is NOT covered

Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.

• Does not cover battery designs using liquid electrolytes exclusively.

• Does not cover non-layered crystal structures or different chemical formulas outside of AxMyO2.

• Does not cover the manufacturing of the anode component itself, only its use in conjunction with the claimed cathode.

• Does not cover high-temperature synthesis methods for these materials.

Who is building on this today

Every major battery manufacturer, including Panasonic, LG Energy Solution, CATL, and Samsung SDI, builds upon the fundamental chemistry established here. While the original patent has long since expired, the basic chemistry of lithium-cobalt-oxide (LCO) remains a standard in the industry.

Products built on expired version of this technology

How to cite this patent in your documentation

Individual. US Patent 4302518. Electrochemical cell with new fast ion conductors. Granted 1981, expired 2000. Now in the public domain.

Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.

PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.