Composite Solid Electrolyte Toughening Against Fracture and Dendrites
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Solution Overview
Problem
Conventional solid electrolytes in solid-state batteries suffer from poor mechanical strength and are prone to fracture, especially when paired with a lithium metal negative electrode, leading to dendrite formation and potential short circuits.
Innovation Solution
A composite solid electrolyte is developed with a phase-transformation toughening agent dispersed in a solid electrolyte substrate, which undergoes phase transformation under external stress to enhance mechanical strength and toughness, preventing defects and crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional solid electrolyte is used, then the battery structure is compact and design flexibility is high, but mechanical strength is poor and fracture resistance is low
Solution Approach 1:
The patent applies composite materials by combining solid electrolyte substrate with phase-transformation toughening agents (such as zirconia particles) to create a composite solid electrolyte. This composite structure provides both the ionic conductivity of the solid electrolyte and the mechanical strength of the toughening agent, resolving the contradiction between maintaining compact battery structure and improving mechanical strength.
2Reliability
If solid electrolyte is paired with lithium metal negative electrode, then energy density is improved, but dendrite formation occurs and short circuit risk increases
Solution Approach 1:
The patent converts the harmful effect of lithium dendrites into a beneficial mechanism by utilizing the phase transformation of zirconia particles. When dendrites grow and apply stress on the electrolyte, the zirconia particles undergo phase transformation that generates compressive stress, which suppresses further dendrite growth and prevents short circuits, thereby improving battery reliability.
Solution Approach 2:
The patent employs phase transitions of zirconia particles (from tetragonal to monoclinic phase) as a mechanical response to external stress. This phase transition mechanism provides dynamic toughening that actively responds to dendrite-induced stress, preventing crack propagation and maintaining battery reliability under operational conditions.
3Strength
If phase-transformation toughening agent is added to enhance toughness, then fracture resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-dispersing phase-transformation toughening agents (zirconia particles) into the solid electrolyte substrate during the manufacturing process. This pre-dispersion ensures uniform distribution of toughening agents throughout the electrolyte layer before battery assembly, simplifying subsequent manufacturing steps while achieving the desired toughness enhancement.
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 composite solid electrolyte improves mechanical strength and toughness, reducing the likelihood of fractures and enhancing the overall performance and reliability of solid-state batteries.
Implementation Method 1
the phase-transformation toughening agent is capable of phase transformation under the action of an external force
Data Source
AI summary
This application relates to a composite solid electrolyte and a preparation method thereof, a solid-state battery, and an electric apparatus, where components of the composite solid electrolyte include a solid electrolyte substrate and a phase-transformation toughening agent dispersed in the solid electrolyte substrate, where the phase-transformation toughening agent is capable of phase transformation under the action of an external force.