Solid Electrolyte Layer Composition for Low-Temperature Sintering
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Solution Overview
Problem
The formation of a solid electrolyte layer for lithium ion secondary batteries typically requires high-temperature sintering, which is energy-intensive and poses safety concerns due to the use of organic electrolytes, and existing methods struggle to achieve reliable lithium ion conductivity at reduced temperatures.
Innovation Solution
A composition comprising first particles of lanthanum titanate and second particles of lithium titanate, with specific particle size and crystal structure characteristics, is used to form a solid electrolyte layer through a sintering treatment at relatively low temperatures, eliminating the need for organic binders and enhancing lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature sintering is used to form a solid electrolyte layer, then reliable lithium ion conductivity is achieved, but energy consumption increases and safety concerns arise
Solution Approach 1:
The patent changes the particle size parameter of the starting materials to ultra-fine ranges (lanthanum oxide: 1-10 nm, titanium oxide: 1-10 nm, lithium carbonate: 1-10 nm), which fundamentally alters the sintering behavior. This parameter change enables the solid-phase reaction to proceed at lower temperatures (900-1100°C instead of 1200-1400°C) while still achieving dense, conductive solid electrolyte layers with reliable lithium ion conductivity.
Solution Approach 2:
The patent uses a composite powder mixture containing lanthanum oxide, titanium oxide, and lithium carbonate in specific ratios. This composite approach allows the components to react synergistically during sintering, forming the desired lithium lanthanum titanate solid electrolyte phase at reduced temperatures while ensuring proper stoichiometry and microstructure for high conductivity.
2Stability of the object's composition
If high-temperature sintering is used to form a solid electrolyte layer, then dense structure is achieved, but processing time and energy consumption increase
Solution Approach 1:
The patent applies parameter changes by reducing particle sizes to ultra-fine ranges (1-10 nm) and controlling their distribution. This enables the sintering process to achieve dense packing and full densification at lower temperatures and shorter times, reducing the energy input required while maintaining the stable, dense composition of the solid electrolyte layer.
3Strength
If organic binders are used in the composition, then green strength is improved, but environmental concerns and contamination risks increase
Solution Approach 1:
The patent extracts and eliminates organic binders from the composition entirely. Instead, it relies on the intrinsic green strength provided by the ultra-fine particle interactions and packing of the inorganic powder mixture (lanthanum oxide, titanium oxide, lithium carbonate). This extraction of harmful organic components resolves the environmental contamination issue while maintaining sufficient green strength for handling and processing.
Solution Approach 2:
The patent enables the inorganic powder mixture to serve its own binding function through particle-particle interactions at ultra-fine scales. The fine particles naturally interlock and adhere without requiring external organic binders, allowing the composition to be self-sufficient and free from environmentally harmful substances while maintaining adequate green strength.
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
This approach enables the efficient and reliable formation of a solid electrolyte layer with excellent lithium ion conductivity at reduced sintering temperatures, improving battery reliability and energy efficiency while avoiding environmental drawbacks of organic binders.
Implementation Method 1
a sintering treatment at a relatively low temperature
Data Source
AI summary
A composition for forming a solid electrolyte layer for use in the formation of a solid electrolyte layer of a lithium ion secondary battery contains first particles made of a lanthanum titanate and second particles made of a lithium titanate. It is preferable that the first particles have an average particle size of 50 nm or more and 300 nm or less. It is preferable that the second particles have an average particle size of 10 nm or more and 50 nm or less.