Lithium-Ion Battery Electrolyte for Low-CB Lithium Deposition Control
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Solution Overview
Problem
Lithium deposition in low CB value regions of lithium-ion batteries leads to decreased capacity and safety issues due to lithium dendrite growth, which is not effectively addressed by existing technologies.
Innovation Solution
Incorporating a metal ion with a higher reduction potential than lithium ions into the electrolyte to suppress lithium deposition and inhibit dendrite growth, thereby improving the capacity retention and cycling performance of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity of the positive electrode active material per unit area is larger than the capacity of the negative electrode active material per unit area in the low CB value region, then the battery can achieve higher overall capacity, but lithium deposition easily occurs at the negative electrode plate
Solution Approach 1:
The patent introduces a metal ion (such as magnesium ion, aluminum ion, zinc ion, or calcium ion) into the electrolyte as an intermediary substance. This metal ion acts as a mediator that competes with lithium ions for deposition sites on the negative electrode, thereby preventing direct lithium deposition while allowing the battery to operate with high positive electrode capacity. The metal ion forms an alloy with lithium or deposits as metal simple substance, serving as a protective intermediary layer.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by adding specific metal ions with controlled concentrations (0.001 M to 1 M). This parameter change modifies the electrochemical behavior at the negative electrode surface, altering the deposition potential and kinetics to suppress lithium dendrite formation while maintaining high capacity operation.
2Quantity of substance
If lithium deposition occurs at the negative electrode plate in the low CB value region, then the battery can accommodate higher positive electrode capacity, but the cycling performance and safety are adversely affected
Solution Approach 1:
The metal ion in the electrolyte serves as a protective intermediary that prevents direct lithium deposition on the negative electrode. During cycling, the metal ion accumulates at the negative electrode surface and forms an alloy with deposited lithium or deposits as metal simple substance, creating a protective layer that maintains electrode integrity over extended cycling periods and improves long-term performance durability.
Solution Approach 2:
The patent converts the potentially harmful lithium deposition into a beneficial process by introducing metal ions that form stable alloys with lithium. The lithium that would otherwise form dangerous dendrites is now converted into stable lithium-metal ion alloys, transforming a safety hazard into a performance-enhancing mechanism that improves cycling stability.
3Device complexity
If lithium deposition occurs at the negative electrode plate, then the battery structure remains simple, but dendrite growth reduces battery safety and performance
Solution Approach 1:
The metal ion acts as a simple chemical intermediary added to the electrolyte that passively prevents dendrite growth without requiring complex structural modifications. The metal ion naturally accumulates at the negative electrode surface and forms a protective alloy layer, providing safety enhancement through a simple compositional change rather than structural complexity.
Solution Approach 2:
The patent suppresses dendrite growth by changing the electrochemical parameters of the electrolyte through metal ion addition. This simple parameter change (electrolyte composition) fundamentally alters the deposition behavior at the negative electrode, preventing dendrite formation without requiring complex battery design modifications.
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 introduction of a metal ion with appropriate reduction potential and concentration in the electrolyte effectively suppresses lithium deposition, enhancing the capacity retention and cycling performance of lithium-ion batteries.
Implementation Method 1
the metal ion in the electrolyte can freely move to a position of lithium deposition and be reduced to a metal simple substance by lithium
Implementation Method 2
a reduction potential of the metal ion is higher than a reduction potential of a lithium ion
Implementation Method 3
enhancing the lithium-ion battery's capacity retention and cycling performance by forming an alloy with lithium
Data Source
AI summary
Embodiments of the present application disclose a lithium-ion battery and an electric device. The lithium-ion battery includes an electrolyte including a metal ion, where a reduction potential of the metal ion is higher than a reduction potential of a lithium ion; and a low CB value region, where a CB value of the lithium ion in the low CB value region satisfies: 0<CB<1, and the CB value is a ratio of a capacity of a negative electrode active material per unit area to a capacity of a positive electrode active material per unit area. The lithium-ion battery provided in the present application can effectively solve the problem of lithium deposition in the low CB value region.