Apple is working with the U.S. Government on new Coatings for Cathode Active Materials for Mobile Batteries & Beyond
On Thursday the US Patent & Trademark Office published a patent application from Apple relates to cathode active materials for lithium-ion batteries. What stood out about this particular battery patent was a notice posted by Apple as follows:
"This invention was made with U.S. government support under WFO Proposal No. 85F59. This invention was made under a CRADA 1500801 between Apple Inc. and Argonne National Laboratory operated for the United States Department of Energy. The U.S. government has certain rights in the invention."
According to Apple, a coating, such as aluminum oxide (Al.sub.2O.sub.3) or aluminum fluoride (AlF.sub.3), is typically applied to the cathode particles to prevent dissolution of the transition metals from the cathodes into the electrolyte. However, the aluminum oxide coating often causes energy density loss for the battery. There remains a need to develop coatings for improved battery performance.
The performance of batteries can be improved using coatings that provide improved average voltage and energy retention.
The Apple-US Government invention covers a combination of surface coating and lithium-ion cathode materials that can demonstrate improved average voltage and cycle retention over a conventional alumina coating.
The disclosure provides the use of lithium-ion oxide containing lanthanum and titanium (LLTO) or lithium-ion oxide containing lanthanum and germanium (LLGO) as lithium-ion conducting coatings for lithium substituted-cobalt oxide based cathode materials. Cathode active materials (e.g. substituted LiCoO.sub.2 cathode materials) coated with the LLTO or LLGO can provide an increased average voltage and an improved energy retention over the conventional alumina coating.
FIG. 2A is a side view of a set of layers for a battery. To create the battery cell, the set of layers may be stacked in a planar configuration, or stacked and then wrapped into a wound configuration; FIG. 2B is a sectional view of a coated particle including a cathode active compound particle and a coating.
The electrochemical performance of the cathode is illustrated as a series of voltage vs. discharge capacity after charge/discharge cycles in FIG. 7 which is a plot of voltage-capacity profile on the charge/discharge of lithium lanthanum germanium oxide (LLGO) coated Li.sub.1.00 (C.sub.O0.99Mn.sub.0.01)O.sub.2.
Apple's patent claims that the invention could apply to an iPhone, iPad, iPod, Apple Watch, a TV monitor, Apple TV. The batteries could apply to Macs and accessories and more.
Apple's patent application was made public on Thursday February 11, 2021 under number 20210043926. Considering that this is a patent application, the timing of such a product to market is unknown at this time.