Porous Battery Separator for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries face issues with nonuniform current density and lithium ion concentration during cycling, leading to lithium dendrite formation, which reduces deposition density and impairs cycle life.
Innovation Solution
A separator with nanoscale and sub-nanoscale pore structures, comprising a polymer layer and a porous material layer with metal-organic framework, covalent organic framework, or molecular sieve materials, that confines solvent molecules and enhances lithium ion mobility, reducing side reactions and dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional separator is used in lithium metal batteries, then the battery can operate, but lithium dendrites form due to nonuniform current density and lithium ion concentration, reducing cycle life
Solution Approach 1:
The patent employs a separator with controlled porous structure (pore size 0.03-1 μm, porosity 30-80%) to regulate lithium ion transport. The porous structure enables uniform current density distribution and prevents lithium dendrite formation by controlling the deposition morphology, thereby resolving the contradiction between maintaining battery operation and preventing harmful dendrite growth while extending cycle life.
Solution Approach 2:
The patent modifies key parameters of the separator including pore size (0.03-1 μm), porosity (30-80%), and thickness (3-20 μm) to optimize lithium ion transport and current density uniformity. By adjusting these parameters, the separator achieves uniform lithium ion concentration distribution during cycling, preventing dendrite formation and extending battery cycle life without compromising operational reliability.
2Productivity
If the separator porosity is increased to improve lithium ion mobility, then electrochemical performance improves, but side reactions between lithium metal and electrolyte solution increase
Solution Approach 1:
The patent optimizes the porosity parameter to a specific range (30-80%) to balance lithium ion mobility and side reaction suppression. This controlled porosity enables sufficient ion transport for high electrochemical performance while maintaining enough structural integrity to reduce electrolyte contact with lithium metal, thereby minimizing side reactions.
Solution Approach 2:
The patent uses composite separator structures combining different materials with complementary properties. The composite structure achieves both high lithium ion conductivity (for improved productivity) and reduced side reactions by selecting materials that provide appropriate pore architecture and chemical stability.
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 separator improves cycle performance by reducing side reactions, increasing lithium deposition density and uniformity, and prolonging the cycle life of lithium metal batteries by confining electrolyte solution and homogenizing lithium ion flow.
Implementation Method 1
the separator with the above features is capable of confining solvent molecules in the electrolyte solution within the pore channels of the separator
Implementation Method 2
increases the density and uniformity of lithium metal deposited on the surface of the negative electrode plate
Implementation Method 3
increases the mobility of lithium ions and improves the electrochemical performance of the electrochemical device
Data Source
AI summary
A separator includes a polymer layer and a porous material layer. The porous material layer includes a porous material. The porous material includes a metal-organic framework material, a covalent organic framework material, a molecular sieve material, or a microporous polymer. The separator contains nanopores and sub-nanopores. By applying the separator to an electrochemical device, solvent molecules in an electrolyte solution can be confined within pore channels of the separator while the electrolyte solution penetrates the separator, thereby not only reducing side reactions between lithium metal and the electrolyte solution during cycling of the electrochemical device and improving the cycle performance of the electrochemical device, but also increasing the mobility of lithium ions and improving the electrochemical performance of the electrochemical device.