POSS-PEG Cross-linked Solid Polymer Electrolytes for Lithium Metal Batteries

Solution Overview

Problem

Current lithium metal batteries face safety issues due to lithium dendrite growth, which can lead to short-circuits and explosions, especially at high current densities, and existing solid polymer electrolytes (SPEs) fail to effectively inhibit this growth.

Innovation Solution

A new class of cross-linked solid polymer electrolytes (SPEs) is developed using polyhedral oligomeric silsesquioxanes (POSS) and amine-terminated poly(ethylene glycol) (PEG), synthesized via a facile one-pot reaction, which provides high ionic conductivity and mechanical strength to prevent lithium dendrite growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional solid polymer electrolytes are used, then the battery structure is simple, but lithium dendrite growth occurs leading to safety issues

Engineering Contradiction:

ImprovesafetyVSAvoidelectrolyte structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite materials by combining POSS nanoparticles with PEO polymer matrix to create a hybrid electrolyte system. The POSS-PEG cross-linked networks form a composite structure that leverages the mechanical strength of POSS and the ion-conducting properties of PEO, effectively suppressing lithium dendrite growth while maintaining safety

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating cross-linked networks at specific locations within the electrolyte matrix. The POSS-PEG cross-linked structures are distributed throughout the PEO matrix, providing localized mechanical reinforcement and dendrite suppression zones that enhance overall safety without requiring complete structural redesign

Inventive Principle:

Principle #3Local quality

2Productivity

If high current densities are applied, then the productivity increases, but lithium dendrite growth accelerates causing short-circuits

Engineering Contradiction:

Improvecharging rateVSAvoiddendrite resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes physical parameters by optimizing the cross-linking density and POSS nanoparticle concentration in the electrolyte. By adjusting these parameters, the electrolyte achieves optimal mechanical strength to resist dendrite growth at high current densities while maintaining sufficient ionic conductivity for high-rate charging

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the mechanical strength of electrolyte is increased to suppress dendrites, then the dendrite resistance improves, but the ion conductivity may decrease

Engineering Contradiction:

Improvedendrite resistanceVSAvoidion conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating cross-linked networks at specific locations within the electrolyte matrix. The POSS-PEG cross-linked structures are distributed throughout the PEO matrix, providing localized mechanical reinforcement and dendrite suppression zones that enhance overall safety without requiring complete structural redesign

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters by optimizing the cross-linking density and POSS nanoparticle concentration in the electrolyte. By adjusting these parameters, the electrolyte achieves optimal mechanical strength to resist dendrite growth at high current densities while maintaining sufficient ionic conductivity for high-rate charging

Inventive Principle:

Principle #35Parameter changes

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 hybrid SPEs exhibit superior resistance to lithium dendrite growth even at high current densities, ensuring stable cycling and rate capability, thus enhancing the safety and performance of lithium metal batteries.

Implementation Method 1

A new class of hybrid electrolytes based on POSS nanoparticles with controlled network structures have been designed and prepared using a facile one-pot reaction

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

SPEs with high room temperature ion conductivity (≈0.1 mS/cm) or with high ionic conductivity (>1 mS/cm) combined with high storage modulus

Methodology Applied

Scientific EffectIon Conduction: Conduction (electrical)

Data Source

PatentUS10622671B2Hybrid electrolytes with controlled network structures for lithium metal batteries

Publication Date: 2020.04.14 DREXEL UNIV

AI summary

Solid polymer electrolytes (SPEs) with tunable network structures are prepared by a facile one-pot reaction of polyhedral oligomeric silsesquioxane (POSS) and poly(ethylene glycol) (PEG). These SPEs with high conductivity and high modulus exhibit superior lithium dendrite growth resistance even at high current densities. Measurements of lithium metal batteries with a LiFePO4 cathode show excellent cycling stability and rate capability. Also disclosed are products made by the process of the invention and batteries including such products.