Elastomer Anode-Protecting Layer for Dendrite-Stable Lithium Metal Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium metal batteries face issues with dendrite formation leading to internal short circuits and thermal runaway, and detrimental reactions between lithium metal and electrolyte, which reduce energy density and stability.
Innovation Solution
A lithium metal secondary battery design featuring an anode-protecting layer made of an elastomer with high recoverable tensile strain and lithium ion conductivity, eliminating the need for a porous separator, and using non-solid state electrolytes to facilitate uniform lithium ion transport and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a lithium metal anode is used to achieve high energy density, then the energy density is significantly higher than lithium ion batteries, but dendrite formation occurs during cycling leading to safety issues and internal short circuits
Solution Approach 1:
The patent introduces an elastomer-based protective layer as an intermediary between the lithium metal anode and the electrolyte. This layer has high lithium ion conductivity to facilitate ion transport while mechanically preventing dendrite formation and penetration, thus resolving the contradiction between high energy density and safety
Solution Approach 2:
The patent employs a thin elastomer film with high tensile strain capability that can flexibly accommodate volume changes of lithium metal during cycling while maintaining structural integrity to prevent dendrite-related failures, enabling both high energy density and reliable operation
2Reliability
If complex anode structures with multiple protective layers are implemented to prevent dendrite formation, then safety is improved, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts and eliminates the porous separator component from the battery structure by integrating its protective function directly into the elastomer layer at the anode, thereby preventing dendrite formation without adding structural complexity
Solution Approach 2:
The elastomer layer performs multiple functions simultaneously: it protects against dendrite formation, conducts lithium ions with high efficiency, and provides mechanical flexibility to accommodate volume changes, replacing the need for multiple separate protective layers and simplifying the overall structure
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 solution effectively prevents dendrite formation, maintains stable lithium ion transport, and enhances cycle life and energy density by ensuring uninterrupted lithium ion re-deposition, reducing the formation of 'dead lithium' and improving safety.
Implementation Method 1
an elastomer having a fully recoverable tensile elastic strain from 2% to 1,000% and a lithium ion conductivity from 10−8 S/cm to 5×10−2 S/cm
Implementation Method 2
an elastomer having a fully recoverable tensile elastic strain from 2% to 1,000%
Data Source
AI summary
The invention provides a method of improving the cycle-life of a lithium metal secondary battery containing a non-solid state electrolyte, the method comprising implementing an anode-protecting layer between an anode active material layer and a cathode active material layer without using a porous separator, wherein the anode-protecting layer is in a close physical contact with the anode active material layer, has a thickness from 1 nm to 100 μm and comprises an elastomer having a fully recoverable tensile elastic strain from 2% to 1,000% and a lithium ion conductivity from 10−8 S/cm to 5×10−2 S/cm when measure at room temperature and wherein the anode active material layer contains a layer of lithium or lithium alloy, in a form of a foil, coating, or multiple particles aggregated together, as an anode active material.