United States Patent and Trademark Office
A major barrier in battery technology concerns safety requirements, particularly when batteries are overheated or overcharged, resulting in thermal runaway, cell breakdown and possibly fire or explosion. Additionally, a short circuit or a design defect may also bring about battery failure resulting in fire and safety risks. Lithium ion batteries in particular, while having operational advantages, are potentially flammable due to their high reactivity, particularly when in contact with humidity.
The present invention relates to the field of energy storage devices, and more particularly, to method of preparing fast charging lithium ion batteries.
This disclosure covers improved anodes and cells, which enable fast charging rates with enhanced safety due to much reduced probability of metallization of lithium on the anode, preventing dendrite growth and related risks of fire or explosion.
Anodes and/or electrolytes have buffering zones for partly reducing and gradually introducing lithium ions into the anode for lithiation, to prevent lithium ion accumulation at the anode electrolyte interface and consequent metallization and dendrite growth.
The disclosed method covers various anode active materials and combinations, modifications through nanoparticles, and a range of coatings that implement the improved anodes, including a method for preparing a lithium ion cell comprising:
attaching nanoparticles to anode active material particles that comprise 5-80% tin, wherein the nanoparticles are at least one order of magnitude smaller than the anode active material particles,
preparing an anode from the anode active material particles having the attached nanoparticles, and
preparing a lithium ion cell using the prepared anode.