LISICON Solid-State Battery Composition for Low Leakage Current
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Solution Overview
Problem
Existing solid-state batteries face issues with low use rate of negative electrode active material and high leakage current, leading to decreased energy density and storage characteristics.
Innovation Solution
A solid-state battery design incorporating a negative electrode layer with a specific molar ratio of Li to V in the negative electrode active material and a solid electrolyte layer with a LISICON-type structure, containing V, to enhance bondability and reduce side reactions during co-sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solid electrolyte with LISICON-type structure containing V is used to suppress side reactions during co-sintering, then the bondability between electrode and electrolyte is improved, but the leakage current becomes excessively high and the use rate of negative electrode active material becomes excessively low
Solution Approach 1:
The patent applies parameter changes by precisely controlling the V content in the LISICON-type solid electrolyte to be 0.01-0.50 atomic ratio and the Li/V molar ratio in the negative electrode active material to be 2.0 or more. These specific parameter ranges optimize both bondability and leakage current suppression, resolving the technical contradiction between improved bonding and reduced leakage current.
Solution Approach 2:
The patent applies local quality by creating different compositional zones: the solid electrolyte layer contains V at a controlled concentration (0.01-0.50 atomic ratio) to provide local bonding enhancement at the interface, while the bulk electrolyte maintains low V content to minimize leakage current. The negative electrode active material also has a specific local composition with Li/V molar ratio of 2.0 or more at the interface region.
2Productivity
If the V content in the solid electrolyte is increased to improve bondability, then the use rate of negative electrode active material is improved, but the leakage current increases excessively
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range for V content (0.01-0.50 atomic ratio) rather than simply increasing it. This controlled parameter change ensures sufficient use rate improvement while preventing excessive leakage current, demonstrating that moderate optimization is more effective than maximization.
3Quantity of substance
If the Li/V molar ratio in the negative electrode active material is increased to improve use rate, then the energy density increases, but the storage characteristics deteriorate due to higher leakage current
Solution Approach 1:
The patent applies parameter changes by setting the Li/V molar ratio to 2.0 or more in the negative electrode active material while simultaneously controlling the V content in the solid electrolyte to 0.01-0.50 atomic ratio. This coordinated parameter optimization achieves high energy density through improved Li insertion/extraction while suppressing leakage current to maintain good storage characteristics over time.
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 design improves the use rate of the negative electrode active material and reduces leakage current, resulting in higher energy density and better storage characteristics.
Implementation Method 1
a solid electrolyte having a lithium super ionic conductor (LISICON)-type structure
Implementation Method 2
an oxide containing vanadium (V) is used as a negative electrode active material for a solid-state battery
Data Source
AI summary
A solid-state battery that includes a negative electrode layer and a solid electrolyte layer. The negative electrode layer contains a negative electrode active material in which a molar ratio of Li to vanadium (V) is 2.0 or more, the solid electrolyte layer contains a solid electrolyte having a lithium super ionic conductor (LISICON)-type structure and containing at least V, and the solid electrolyte contained in the solid electrolyte layer has an average chemical composition represented by (Li[3−ax+(5−b)(1−y)]Ax)(VyB1−y)O4.