Microporous Spirobisindane Separator for Lithium Dendrite Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium metal batteries face challenges with irreversible capacity loss and dendrite formation due to parasitic reactions between the lithium anode and electrolyte, leading to uneven plating and potential thermal runaway, which hinders their commercialization.

Innovation Solution

A polymer of Formula I or its salt, comprising specific heterocycloalkyl and heteroaryl groups, is used as a separator in lithium metal batteries to enhance the stability and prevent dendrite growth, formed through a reaction mixture with a non-nucleophilic base and a solvent, improving the mechanical integrity and ion transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal anodes are used to increase energy density, then battery capacity is improved, but parasitic reactions with electrolyte cause irreversible capacity loss and dendrite formation

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A polymer coating layer comprising spirobisindane polymers of intrinsic microporosity is applied between the lithium metal anode and electrolyte. This intermediary layer prevents direct parasitic reactions while maintaining lithium ion transport, thereby preserving battery capacity across charge-discharge cycles and preventing dendrite formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The spirobisindane polymers possess intrinsic microporosity that allows selective lithium ion transport while blocking larger electrolyte molecules. This porous structure enables the coating to maintain high ionic conductivity necessary for battery operation while preventing harmful parasitic reactions between lithium metal and electrolyte components.

Inventive Principle:

Principle #31Porous materials

2Strength

If ceramic coatings are applied to separators to block dendrites, then mechanical properties are improved, but parasitic reactions are induced at the anode by binding materials

Engineering Contradiction:

Improvemechanical integrityVSAvoidparasitic reactions

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The polymer coating uses a thin, sacrificial layer of spirobisindane polymer that can be applied as a conformal coating on the separator surface. This disposable-like layer prevents parasitic reactions and dendrite formation without requiring the robust but reactive ceramic coatings and their binding materials.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Speed

If porous polymer coatings are applied to increase separator wettability, then ion transport is improved, but the complexity of multi-layer structures increases

Engineering Contradiction:

Improveion transportVSAvoidseparator structure

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The invention merges the separator substrate with a conformal polymer coating into a integrated separator structure. The spirobisindane polymer is applied directly to the separator surface, combining the mechanical support function with the ion-transport-enhancing coating function, thereby simplifying the overall structure while maintaining high ionic conductivity.

Inventive Principle:

Principle #5Merging (Combining)

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 polymer separator effectively mitigates dendrite formation and enhances the stability and performance of lithium metal batteries by reducing irreversible capacity loss and improving ion transport, thus enabling safer and more stable operation.

Implementation Method 1

Battery separators are a critical component of Li-ion batteries since they isolate the electrodes, providing ion transport through large pores filled with electrolyte

Methodology Applied

Scientific EffectIon transport: Permeation