Fluoroniobate Cathode Electrolyte for Low-Resistance Solid-State Batteries
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Solution Overview
Problem
Conventional all-solid-state lithium secondary batteries experience an increase in internal resistance during charge due to oxidative decomposition of halide solid electrolytes, particularly those containing Cl, Br, or I, which form resistance layers and hinder lithium-ion conductivity.
Innovation Solution
A positive electrode material is developed comprising a solid electrolyte with Li, Nb, and F, where M1 is selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Al, Ga, In, or Sn, providing high oxidation resistance and ionic conductivity to prevent oxidative decomposition and reduce interfacial resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halide solid electrolytes containing Cl, Br, or I are used, then ionic conductivity is improved, but oxidative decomposition occurs during charge forming resistance layers that increase internal resistance
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating elements with high oxidation resistance (Al, Ga, In, Sc, Y) into the halide solid electrolyte structure. This compositional modification maintains the desirable ionic conductivity of halide electrolytes while fundamentally altering the oxidation resistance parameter to prevent decomposition during charging.
Solution Approach 2:
The patent creates a composite solid electrolyte material combining halide components (for ionic conductivity) with oxidation-resistant metal elements (Al, Ga, In, Sc, Y). This composite structure integrates the beneficial properties of both material types: the halide portion provides high Li-ion conductivity while the oxidation-resistant metal portion prevents decompositional reactions during charging.
2Productivity
If solid electrolyte composition is optimized for ionic conductivity, then charge and discharge efficiency is improved, but oxidation resistance may be compromised
Solution Approach 1:
The patent simultaneously optimizes multiple compositional parameters of the solid electrolyte: maintaining the halide structure for high ionic conductivity (productivity) while incorporating specific ratios of oxidation-resistant metals (Al, Ga, In, Sc, Y) to ensure oxidation resistance. This multi-parameter optimization achieves both goals concurrently.
Solution Approach 2:
The composite solid electrolyte structure allows the halide portion to provide high Li-ion conductivity for efficient charge/discharge while the integrated oxidation-resistant metal portion simultaneously provides protection against oxidative decomposition, resolving the trade-off between productivity and reliability.
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 solution effectively suppresses the increase in internal resistance during charge, enhancing the battery's charge and discharge efficiency while maintaining energy density and output characteristics.
Implementation Method 1
a first electrolyte that is a solid electrolyte... the first electrolyte includes Li, Nb, M1, and F
Implementation Method 2
Conventional techniques are desired to suppress an increase in the internal resistance of a battery during charge... the first electrolyte includes Li, Nb, M1, and F... it is possible to suppress an increase in the internal resistance of a battery during charge
Data Source
AI summary
A positive electrode material of the present disclosure includes a positive electrode active material and a first electrolyte that is a solid electrolyte. The first electrolyte includes Li, Nb, M1, and F. The M1 is at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, Sc, Y, Al, Ga, In, Zr, and Sn. A battery of the present disclosure includes a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode. The positive electrode includes the positive electrode material of the present disclosure.