High-Elasticity Polymer Anode Layer for Lithium Metal Battery Dendrite Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium metal batteries face challenges with lithium metal dendrite formation and reactions between lithium metal and electrolyte, leading to internal short circuits and thermal runaway, which have hindered their commercialization due to complexity, cost, and low lithium ion conductivity of solid electrolytes.
Innovation Solution
A lithium secondary battery design featuring a high-elasticity polymer layer with recoverable tensile strain and lithium ion conductivity between the lithium anode and electrolyte, preventing dendrite formation and maintaining ion transport, composed of a polyrotaxane network or similar structure, supported by a current collector or nanofilaments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is applied to the lithium anode to prevent dendrite formation, then safety and cycle stability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
A polymer electrolyte layer is introduced as an intermediary between the lithium anode and the electrolyte. This intermediate layer prevents direct contact between lithium metal and the electrolyte, thereby preventing dendrite formation and improving cycle stability without requiring complex multi-layer structures
Solution Approach 2:
The patent changes the physical and chemical parameters of the protective layer by using a polymer electrolyte with specific properties: lithium ion conductivity ≥10^-6 S/cm, thickness 1 nm to 10 μm, and high elasticity with recoverable tensile strain ≥2%. These parameter optimizations achieve effective dendrite prevention while maintaining simplicity
2Reliability
If a protective layer is applied to the lithium anode to prevent dendrite formation, then safety is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses a polymer electrolyte layer that can be easily manufactured and potentially replaced, rather than requiring expensive solid electrolytes or complex multi-layer protective structures. The polymer electrolyte provides adequate protection at lower cost
Solution Approach 2:
By optimizing the thickness parameter to 1 nm to 10 μm and selecting polymer electrolytes with appropriate lithium ion conductivity (≥10^-6 S/cm), the patent achieves effective safety improvement while minimizing material cost and manufacturing complexity
3Reliability
If solid electrolyte is used to prevent dendrite formation, then safety is improved, but lithium ion conductivity decreases
Solution Approach 1:
The patent specifies that the polymer electrolyte must have lithium ion conductivity of at least 10^-6 S/cm, which is significantly higher than traditional solid electrolytes. This parameter optimization allows the protective layer to maintain both safety and adequate ion transport capability
Solution Approach 2:
The patent uses polymer electrolytes that combine the benefits of solid electrolytes (dendrite prevention) with liquid electrolytes (high ion conductivity). The polymer matrix provides structural integrity and dendrite suppression, while the lithium salt complexes provide high ion conductivity
4Quantity of substance
If excessive lithium is used to compensate for dendrite formation and reactions, then capacity is maintained, but energy density decreases
Solution Approach 1:
The polymer electrolyte layer is applied in advance to prevent dendrite formation and lithium-electrolyte reactions before they can occur. By preventing these parasitic reactions upfront, the patent eliminates the need to add excess lithium metal to compensate for capacity loss, thereby maintaining high energy density
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 high-elasticity polymer layer effectively prevents dendrite formation, ensures uniform lithium ion deposition, and enhances cycle stability and safety, reducing the need for excessive lithium and improving energy density.
Implementation Method 1
a thin layer of a high-elasticity polymer having a recoverable tensile elastic strain no less than 2%, a lithium ion conductivity no less than 10−6 S/cm at room temperature
Implementation Method 2
a high-elasticity polymer having a recoverable tensile elastic strain no less than 2%
Data Source
AI summary
Provided is a lithium secondary battery, comprising a cathode, an anode, and a porous separator or electrolyte disposed between the cathode and the anode, wherein the anode comprises: (a) an anode active layer containing a layer of lithium or lithium alloy, in a form of a foil, coating, or multiple particles aggregated together, as an anode active material; and (b) a thin layer of a high-elasticity polymer, disposed between the anode active layer and the porous separator or electrolyte; the polymer having a recoverable tensile strain from 2% to 1,500%, a lithium ion conductivity no less than 10−6 S/cm (typically up to 5×10−2 S/cm) at room temperature, and a thickness from 1 nm to 10 μm, wherein the high-elasticity polymer contains a polyrotaxane network having a rotaxane structure or a polyrotaxane structure at a crosslink point of the polyrotaxane network.