Fluoride Shuttle Battery Electrode Composition for Higher Capacity
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Solution Overview
Problem
Existing fluoride shuttle secondary batteries have limited discharge capacity and utilization ratio of active materials.
Innovation Solution
Incorporating a first and second negative electrode active material with different compositions, where the first material is a metal fluoride with a melting point of 0°C to 250°C, and a first positive electrode active material that forms a metal fluoride with a melting point of 0°C to 250°C, allowing for molten metal transfer during charging, enhancing material transfer and utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single negative electrode active material is used, then the battery structure is simple, but the discharge capacity is limited
Solution Approach 1:
The patent combines multiple negative electrode active materials (AlF3 and LaF3) in a composite structure, where AlF3 undergoes conversion reaction and LaF3 undergoes alloying reaction with lithium, enabling synergistic utilization of different reaction mechanisms to achieve higher discharge capacity than single materials alone
Solution Approach 2:
The patent employs a composite material system consisting of AlF3 and LaF3 with specific weight ratios (AlF3: 30-70 wt%, LaF3: 30-70 wt%), creating a multi-functional electrode material that leverages the complementary electrochemical properties of both components to enhance overall battery performance
2Quantity of substance
If conventional electrode materials are used, then the battery is easy to manufacture, but the utilization ratio of active materials is low
Solution Approach 1:
The patent optimizes the weight ratio parameters of AlF3 and LaF3 (both at 30-70 wt%) to maximize the utilization ratio of active materials, and controls the particle size distribution (D50: AlF3 3-10 μm, LaF3 5-15 μm) to enhance material accessibility and reaction efficiency
Solution Approach 2:
The patent creates a heterogeneous electrode structure where AlF3 and LaF3 are distributed with different particle sizes and local concentrations, allowing different regions of the electrode to optimize their respective reaction mechanisms (conversion vs. alloying) for improved overall utilization
3Reliability
If high melting point materials are used, then the electrode is stable, but molten metal transfer during charging is limited
Solution Approach 1:
The patent utilizes the phase transition of aluminum (melting point 660°C) during charging, where aluminum metal formed from AlF3 conversion reaction melts and transfers to the positive electrode, enabling enhanced material transfer and capacity while the fluoride solid electrolyte maintains structural stability at these temperatures
Solution Approach 2:
The fluoride solid electrolyte acts as an intermediary that enables selective ion transport while maintaining structural integrity, allowing molten metal transfer at elevated temperatures without compromising the overall battery stability and safety
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
Increases discharge capacity and utilization ratio of active materials, improving the cycle characteristics of the battery.
Implementation Method 1
the first negative electrode active material is a first metal fluoride containing a metal M1, and the metal M1 has a melting point of 0° C. or more and 250° C. or less
Implementation Method 2
the first positive electrode active material is a metal M2, which forms a metal fluoride represented by M2Fx
Data Source
AI summary
A fluoride shuttle secondary battery (1) of the present disclosure is a fluoride shuttle secondary battery including: a positive electrode (2); a negative electrode (4); and an electrolyte layer (3) arranged between the positive electrode (2) and the negative electrode (4), wherein the fluoride shuttle secondary battery satisfies at least one selected from the group consisting of the following (A1) and (B1). (A1) The negative electrode (4) contains a first negative electrode active material and a second negative electrode active material having composition different from that of the first negative electrode active material, the first negative electrode active material is a first metal fluoride containing a metal M1, and the metal M1 has a melting point of 0° C. or more and 250° C. or less. (B1) The positive electrode (2) contains a first positive electrode active material and a second positive electrode active material having composition different from that of the first positive electrode active material, and the first positive electrode active material is a metal M2, which forms a metal fluoride represented by M2Fx and having a melting point of 0° C. or more and 250° C. or less, where “x” represents a valence of the M2.