Glass-Ceramic Lithium-Ion Conductor for Dendrite-Resistant Fast Charging
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Solution Overview
Problem
All-solid-state batteries face challenges with dendrite formation during charging, particularly at higher current densities, leading to short circuits, which existing separator materials fail to prevent effectively.
Innovation Solution
A lithium ion-conducting material comprising a crystalline phase, such as Li-stable LLZO, combined with an amorphous phase containing SiO2 and/or P2O5 glass formers, which accumulates at grain boundaries to enhance critical current density and prevent dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing separator materials are used, then the battery structure is simple, but dendrite formation occurs at higher current densities leading to short circuits
Solution Approach 1:
The patent employs a composite separator material consisting of a crystalline lithium ion-conducting phase (such as LLZO - lithium lanthanum zirconate) combined with an amorphous glassy phase. This composite structure leverages the high ionic conductivity of the crystalline phase while the amorphous phase fills grain boundaries and suppresses dendrite growth, achieving superior dendrite resistance without excessive complexity
Solution Approach 2:
The invention applies local quality by creating regions with different properties within the separator: the crystalline phase provides bulk ionic conductivity pathways, while the amorphous glassy phase specifically targets grain boundary regions to prevent dendrite propagation. This localized functional differentiation enhances overall reliability without requiring complete structural redesign
2Productivity
If higher current densities are used for fast charging, then charging speed increases, but dendrite formation becomes easier leading to short circuits
Solution Approach 1:
The patent changes the physical and chemical parameters of the separator material by incorporating specific glass formers (such as SiO2, B2O3, P2O5) in controlled amounts. These compositional parameter changes modify the material's response to high current densities, enabling it to maintain structural integrity and suppress dendrites even during fast charging operations at elevated current densities
Solution Approach 2:
The amorphous glassy phase acts as a preventive cushion against dendrite formation before dendrites can actually form and propagate. By pre-positioning this dendrite-suppressing phase at grain boundaries and interfaces, the material creates a protective barrier that prevents the harmful effect of dendrite growth even when high current densities are applied during fast charging
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 material significantly increases the critical current density to above 0.5 mA/cm2, preventing short circuits and enabling fast charging without dendrite formation, thus ensuring the functionality and safety of all-solid-state batteries.
Implementation Method 1
The amorphous phase is present in the grain boundaries of the sintered separator
Data Source
AI summary
The present invention relates to a lithium ion-conducting material, especially a glass-ceramic, having improved dendrite stability (stability to the formation of dendrites), and to use and a process for production.