Elastic Polymer Separator for Lithium Metal Battery Dendrite Control
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Solution Overview
Problem
Rechargeable lithium metal batteries face challenges due to lithium metal dendrite formation and reactions with the electrolyte, leading to safety concerns, internal short circuits, and rapid capacity decay, which have hindered their commercialization for electric vehicles and electronic devices.
Innovation Solution
An anode-less lithium metal battery design featuring a high-elasticity polymer separator with lithium ion conductivity and fully recoverable tensile strain, eliminating the need for initial lithium at the anode and preventing dendrite formation by maintaining consistent contact between the anode current collector and the separator during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal anode is used to achieve high capacity, then energy density is improved, but dendrite formation occurs leading to safety issues and rapid capacity decay
Solution Approach 1:
A solid polymer electrolyte separator is introduced as an intermediary layer between the lithium metal anode and cathode. This separator acts as a mediator that allows lithium ion transport while physically preventing dendrite penetration and chemical reactions, thereby maintaining both high energy density and cycle stability.
Solution Approach 2:
The patent changes the physical state of the electrolyte from liquid to solid polymer form. This parameter change eliminates dendrite formation and chemical decomposition issues while maintaining lithium ion conductivity, thus resolving the contradiction between energy density and cycle stability.
2Use of energy by moving object
If lithium metal anode is used to achieve high capacity, then energy density is improved, but internal short circuits occur due to dendrite formation
Solution Approach 1:
The solid polymer electrolyte serves as a protective intermediary that physically blocks dendrites from penetrating through the battery cell. This mediator prevents direct contact between anode and cathode, eliminating internal short circuits while preserving the high capacity benefits of lithium metal.
Solution Approach 2:
The patent employs a thin film solid polymer electrolyte that is flexible yet effective at blocking dendrites. This thin film structure provides mechanical barrier protection against short circuits while maintaining ionic conductivity for high energy density operation.
3Use of energy by moving object
If conventional electrolyte is used with lithium metal anode, then high capacity is achieved, but rapid capacity decay occurs due to electrolyte consumption
Solution Approach 1:
The solid polymer electrolyte acts as a stable intermediary that eliminates continuous electrolyte consumption. By replacing liquid electrolyte with solid polymer, the system prevents chemical decomposition and electrolyte loss, thereby extending cycle life while maintaining high capacity.
Solution Approach 2:
Changing the electrolyte from liquid to solid polymer form fundamentally alters the chemical stability parameter. This change eliminates the continuous consumption and decomposition issues that limit cycle life, enabling long-duration high-capacity 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 solution significantly improves cycle stability and energy density by preventing dendrite formation and reducing electrolyte consumption, enabling safer and more efficient lithium metal batteries with extended cycle life.
Implementation Method 1
an elastic polymer separator having a thickness from 50 nm to 100 μm and a lithium ion conductivity from 10‑6 S/cm to 5 × 10‑2 S/cm at room temperature and a fully recoverable tensile strain from 2% to 1,000%
Implementation Method 2
a solid polymer electrolyte-based rechargeable battery
Data Source
AI summary
A lithium metal battery comprising a cathode, an anode, and an elastic polymer separator disposed between the cathode and the anode, wherein the elastic polymer separator comprises a high-elasticity polymer and the elastic polymer separator has a thickness from 50 nm to 100 µm and a lithium ion conductivity from 10-6 S/cm to 5 × 10-2 S/cm at room temperature and the high elasticity polymer has a fully recoverable tensile strain from 2% to 1,000% when measured without any additive dispersed therein. Preferably, the high-elasticity polymer contains a lithium salt and/or a lithium-ion conducting additive dissolved or dispersed therein. Also provided is a process for producing the elastic polymer separator and a lithium metal battery.