Doped Lithium Metal Battery Separator with Metal Oxide Coating
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Solution Overview
Problem
Lithium metal batteries face issues with interfacial instability and dendrite formation due to the high reactivity of lithium metal, and conventional separators exhibit low wettability towards electrolytes, leading to reduced performance and cycle life.
Innovation Solution
A modified separator for lithium metal-based electrochemical cells is developed, comprising a doped substrate with a polymeric or ceramic-type coating layer and an electrolyte system with a viscosity ranging from 50 mPa·s to 500 mPa·s, using dopants like aluminum oxide and titanium dioxide, and a coating layer thickness of 1 nm to 50 nm, which enhances wettability and prevents dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyolefin separators are used in lithium metal batteries, then the battery structure is simple and manufacturing is easy, but the wettability towards electrolyte is low resulting in reduced performance and cycle life
Solution Approach 1:
The patent applies composite materials by combining polyolefin substrate with metal oxide coatings (such as Al2O3, TiO2, ZrO2) to create a separator with improved wettability. The composite structure integrates the mechanical strength of polyolefin with the surface properties of metal oxides, achieving both ease of manufacture and enhanced performance.
Solution Approach 2:
The patent changes the surface parameters of the separator by doping metal oxides and applying coating layers with controlled thickness (1-50 nm). This modifies the surface energy and wettability parameters without fundamentally changing the bulk properties, allowing the separator to better interact with high viscosity electrolytes while maintaining manufacturing simplicity.
2Quantity of substance
If lithium metal is used in the negative electrode to achieve high energy density, then the storage capacity doubles and size is halved, but interfacial instability and dendrite formation occur due to high reactivity
Solution Approach 1:
The metal oxide coating layer acts as an intermediary between the lithium metal anode and the electrolyte. This intermediate layer reduces direct contact between reactive lithium metal and electrolyte species, preventing unwanted side reactions and dendrite formation while still allowing lithium ion transport, thus maintaining high energy density with improved interfacial stability.
Solution Approach 2:
The patent utilizes porous metal oxide coating layers that allow lithium ion diffusion while providing a protective interface. The porous structure enables ion transport necessary for high capacity lithium metal operation while the material composition prevents harmful reactions, resolving the contradiction between energy density and interfacial stability.
3Reliability
If high viscosity electrolyte is used to improve ion conduction, then the electrolyte can better fill separator pores, but the wettability and permeation into separator becomes difficult
Solution Approach 1:
The patent modifies the separator's surface parameters through metal oxide doping and coating, changing the surface energy and wettability characteristics. This enables high viscosity electrolytes to effectively wet and permeate the separator pores, achieving both good ion conduction and complete electrolyte filling without sacrificing ease of operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified separator improves the long-term performance and stability of lithium metal batteries by preventing dendrite formation and ensuring complete electrolyte penetration, resulting in superior cycling performance and reduced capacity fade.
Implementation Method 1
The dopant may be present in an amount ranging from about 1 g/m2 to about 10 g/m2, and the modified separator may have a wettability towards the electrolyte demonstrated by a comparatively low contact angle
Implementation Method 2
The coating layer may be one of a polymeric-type coating layer and a ceramic-type metal oxide coating layer
Data Source
AI summary
A modified separator for a high-energy lithium metal-based electrochemical cell and methods of formation relating thereto are provided. The modified separator includes a substrate including a dopant and a coating layer disposed on the doped substrate. The dopant and compound comprising the coating layer are independently selected from the group consisting of: aluminum oxide (Al2O3), titanium dioxide (TiO2), zirconium dioxide (ZrO2), zinc oxide (ZnO), iron oxide (Fe2O3), tin oxide (SnO), silicon oxide (SiO2), tantalum oxide (Ta2O5), lanthanum oxide (La2O3), hydrofluoroolefin (HfO), cerium oxide (CeO2), and combinations thereof.