StoreDot’s pioneering patent for novel anode coatings counters SEI buildup in fast-charging Li-ion batteries


United States Patent and Trademark Office »

As the world turns to electrification to reduce greenhouse gas emissions, Lithium-ion batteries dominate electrical energy storage systems, powering everything from portable electronic devices to electric vehicles (EVs). This increase in the number and variety of applications is driving a demand for higher energy density, enhanced safety, and faster charging batteries. To meet these wide-ranging requirements researchers are exploring new innovative materials and processes to unlock even more performance from the Li-ion battery.

One of the greatest challenges researchers and manufacturers face in improving performance, particularly in fast-charging batteries used in EVs, is the control of the degradation of the interface between the anode and the electrolyte.

During fast charging, the electrolyte at the anode-electrolyte interface can decompose, leading to the formation of a solid-electrolyte interphase (SEI). This SEI layer impedes the free movement of lithium ions, resulting in increased resistance and reduced battery capacity. Additionally, the direct contact between the electrolyte and the anode material particles can trigger parasitic reactions, further degrading the battery's performance.

StoreDot’s patented innovation describes methods of applying a coating of ionic-conductive polymer to the anode that acts as an artificial SEI. By allowing lithium ion transfer through the coating, while preventing the electrolyte from coming into direct contact with the anode material particles, the degradation of the interface between the anode and the electrolyte can be controlled.

United States Patent and Trademark Office: Anode coating in lithium-ion batteries »

StoreDot's patented invention describes the methodology of composition and application of a novel anode coating that allows lithium ions to move through the coating while preventing the electrolyte from coming into direct contact with the anode material particles. This moderates SEI formation, thereby enhancing cell stability and increasing cycling lifetime.

The patent outlines methods of coating the anode material particles with a microscopic layer of ionic-conductive polymer. The ionic-conductive polymer used in the coating can be made from any of a number of compounds, including (but not limited to): Poly Acrylic Acid, Poly Vinylene Carbonate, Poly Vinyl Pyrrolidone, Poly Vinyl Butyral, thermoset polyimides, and hydroxypropyl cellulose. These polymers offer excellent ionic conductivity and are soluble in organic solvents, thereby simplifying the application process.

To further simplify manufacture and ensure scalability, the coating can be applied through a wide range of proven techniques, including spray coating, impregnation, dip coating, spin coating, grit blasting, ultrasonic drenching, and application of light curing using UV, air, heat, or chemical treatment. What is more, under certain conditions the polymerization of the coating can be performed in situ. This in situ polymerization allows for better coating efficiency and coverage, resulting in a more stable coating layer.

StoreDot's patent on anode coating for lithium-ion batteries represents a significant advancement in the field of energy storage, in particular, fast-charging batteries as used in EVs, including:

  • Enhanced Battery Performance: The artificial SEI layer provided by the anode coating facilitates the transfer of lithium ions, reducing the resistance and improving the battery's overall performance. This allows for faster charging and discharging rates, making it ideal for fast-charging EV applications.
  • Increased Cycling Lifetime: The anode coating prevents direct fluid communication between the electrolyte and the anode material particles, reducing parasitic reactions and degradation. This leads to increased cycling lifetime and improved battery longevity.
  • Improved Safety: By preventing direct contact between the electrolyte and the anode material particles, the anode coating minimizes the risk of electrolyte decomposition and thermal runaway. This makes the batteries safer to use, especially in high-demand applications such as fast-charging EVs.

The innovative methodology and composition described in StoreDot’s patent offer a promising solution to the challenges associated with the fast charging and degradation of lithium-ion batteries. With its wide range of applications and benefits, StoreDot's anode coating technology has the potential to revolutionize fast-charging Li-ion EV batteries, paving the way for a more sustainable and rapid rollout of EVs.

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