How a Hybrid Layer Stops Metal Growths in Lithium Batteries

This patent describes a special multi-layered electrolyte system for lithium metal batteries that uses a stiff, hybrid material to block dangerous metal growths, aiming for safer, higher-energy batteries.

What it covers

This patent describes an electrolyte system designed for electrochemical cells, especially lithium metal batteries, to prevent the formation of dendrites. It features a solid dendrite-blocking layer that is both ionically conducting (lets ions pass) and electrically insulating (stops electrons, preventing short circuits). This blocking layer, as described in Claim 1, has a high shear modulus of at least 7.5 GPa at 23° C, meaning it's very stiff. It's a hybrid, made from a solid-state ceramic, glass, or glass-ceramic (like lithium phosphorous sulfide) combined with a solid-state polymer, specifically polyethylene oxide. This blocking layer sits between a first liquid electrolyte (which interfaces with the positive electrode) and an interface layer. The interface layer, in turn, connects to the negative electrode (which contains lithium metal) and can be a second liquid electrolyte, a gel polymer electrolyte, or a solid-state electrolyte. For example, in an electric car battery, this system would allow lithium ions to move efficiently while physically stopping lithium metal dendrites from growing and causing a short circuit.

What it doesn't cover

• —Electrolyte systems that do not include a solid dendrite-blocking layer.
• —Dendrite-blocking layers that are not a hybrid of a solid-state ceramic/glass and a solid-state polymer like polyethylene oxide.
• —Dendrite-blocking layers with a shear modulus less than 7.5 GPa at 23° C.
• —Electrolyte systems where the dendrite-blocking layer is not positioned between a first liquid electrolyte and an interface layer.
• —Systems that lack the specific interface layer comprising a second liquid, gel polymer, or solid-state electrolyte.
• —Dendrite prevention methods that rely solely on chemical additives without a physical, high-shear-modulus blocking layer.

The clever bit

The novelty lies in combining a high mechanical strength (a shear modulus of at least 7.5 GPa) with ionic conductivity in a hybrid material (ceramic/glass and polymer) to physically stop dendrite growth. This unique combination allows lithium ions to pass through while being tough enough to block the problematic metal structures, which was a significant hurdle for lithium metal battery development.

Why it matters

Lithium metal batteries hold the promise of significantly higher energy density compared to current lithium-ion batteries, meaning devices could last longer or be lighter. However, a major challenge is the formation of lithium dendrites, which are tiny, tree-like metal growths that can pierce the separator, causing short circuits, overheating, and even fires. This patent offers a solution to this critical safety and performance issue by introducing a robust physical barrier, potentially enabling the widespread adoption of safer and more powerful lithium metal batteries in electric vehicles and portable electronics.

Real-world examples

• 1.Next-generation electric vehicle batteries
• 2.High-capacity batteries for portable electronics
• 3.Grid-scale energy storage systems
• 4.Aerospace and drone battery applications