Liquid-Metal Alloy Negative Electrode for Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face issues with negative electrodes cracking due to significant volume expansion and contraction during lithium insertion and extraction, leading to reduced cycle life.
Innovation Solution
A liquid-metal alloy negative electrode layer is introduced, where the alloy components have a melting point below the battery operating temperature, eliminating cracking by remaining in a liquid state and absorbing volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid metal negative electrodes are used, then structural integrity is maintained, but cracking occurs due to volume expansion and contraction during lithium insertion and extraction
Solution Approach 1:
The patent changes the physical state parameter of the negative electrode material from solid to liquid by using a eutectic alloy composition (67-80 wt% Ga, 10-20 wt% In, 10-25 wt% Zn) with melting point below battery operating temperature. This parameter change allows the material to remain in liquid state during operation, eliminating cracking while maintaining reliability
Solution Approach 2:
The patent employs a composite structure consisting of a eutectic alloy composition (Ga-In-Zn) that combines multiple metals to achieve a melting point below battery operating temperature. This composite material approach enables the negative electrode to function as a liquid while maintaining structural integrity through the container
2Reliability
If liquid metal alloy is used for negative electrode, then cracking is eliminated and cycle life is enhanced, but the material must be maintained in liquid state requiring specific temperature control
Solution Approach 1:
The patent modifies the melting point parameter of the negative electrode material by selecting a eutectic composition (67-80 wt% Ga, 10-20 wt% In, 10-25 wt% Zn) with melting point below battery operating temperature. This ensures the material remains liquid within the normal operating temperature range of lithium-ion batteries without requiring additional heating or cooling systems
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 use of a liquid metal alloy negative electrode enhances cycle life by preventing cracking and maintaining battery performance over repeated charging and discharging cycles.
Implementation Method 1
The process of lithium-ion insertion and extraction results in a large volume expansion and contraction in some negative electrodes. This expansion and contraction can approach three hundred percent, which may make the negative electrodes prone to cracking as the battery cycles between charging and discharging.
Implementation Method 2
Because the alloy component of the negative electrode layer is in a liquid state, cracks typically caused by volume changes associated with lithium insertion and extraction in conventional solid metal negative electrodes can be eliminated.
Data Source
AI summary
One embodiment includes a liquid-metal alloy negative electrode for a lithium-ion battery. The electrode may also include a porous matrix that comprises a polymer matrix material, a hydrogel material, or a ceramic material.