Lanthanum Negative Electrode Layer for Low-Impedance Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The migration speed of lithium ions in lithium-ion batteries is limited, leading to increased internal polarization, which affects the rate and cycling performance of these batteries.
Innovation Solution
A secondary battery design with a negative electrode plate containing a negative electrode material layer composed of a negative electrode active material, a solid electrolyte material with lanthanum, and a negative electrode binder, where the mass percentage of lanthanum is controlled between 0.16% and 5%, enhancing ionic conductance and reducing impedance through catalytic effects on the electrolyte solution, thereby improving cohesion and reducing swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the charge rate is increased, then the power output is improved, but the internal polarization increases due to limited lithium ion migration speed
Solution Approach 1:
The patent changes the physical and chemical parameters of the negative electrode material layer by incorporating solid electrolyte material containing lanthanum. This modification alters the ionic conductance properties of the electrode, enabling faster lithium ion migration speeds that can keep pace with increased charge rates, thereby reducing internal polarization while maintaining high power output
Solution Approach 2:
The patent creates a composite negative electrode material layer combining traditional negative electrode active material with solid electrolyte material containing lanthanum. This composite structure leverages the electrochemical activity of the active material while utilizing the high ionic conductance of the solid electrolyte component to accelerate lithium ion transport, resolving the contradiction between power output and internal polarization
2Reliability
If the ionic conductance is improved by adding solid electrolyte material, then the impedance is reduced, but the cohesion of the negative electrode material layer deteriorates
Solution Approach 1:
The patent optimizes the concentration parameter of lanthanum in the solid electrolyte material within the specific range of 0.16-5 mass%. This parameter optimization achieves a balance where the ionic conductance is sufficiently improved to reduce impedance, while the cohesion of the negative electrode material layer is maintained within acceptable limits (15-45 N/m)
Solution Approach 2:
The patent applies local quality enhancement by specifically positioning the solid electrolyte material containing lanthanum within the negative electrode material layer. The lanthanum-rich regions provide localized pathways for rapid lithium ion conduction, reducing overall impedance while the surrounding matrix maintains the structural cohesion of the electrode
3Stability of the object's composition
If the cohesion of the negative electrode material layer is increased, then the swelling is reduced, but the ionic conductance deteriorates
Solution Approach 1:
The patent employs a composite negative electrode material layer that integrates negative electrode active material, solid electrolyte material containing lanthanum, and negative electrode binder. This composite structure resolves the contradiction by allowing the solid electrolyte component to provide high ionic conductance while the binder and active material matrix maintain structural cohesion and reduce swelling during cycling
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 battery achieves improved rate and cycling performance by lowering impedance and reducing negative electrode swelling, with the solid electrolyte material accelerating lithium ion conduction and enhancing bonding between components.
Implementation Method 1
The solid electrolyte material in the negative electrode material layer can improve the ionic conductance of the negative electrode plate and lower the impedance of the secondary battery
Implementation Method 2
Lanthanum in the solid electrolyte material has a catalytic effect on the electrolyte solution. With the percentage of lanthanum being controlled within the range in this application, the electrolyte solution can be further polymerized, and the bonding between the solid electrolyte material and the negative electrode active material is enhanced
Data Source
AI summary
A secondary battery includes a negative electrode plate, wherein the negative electrode plate includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, and a cohesion of the negative electrode material layer is Z N/m, wherein 15≤Z≤45; and the negative electrode material layer includes a negative electrode active material, a solid electrolyte material, and a negative electrode binder, the solid electrolyte material includes lanthanum, and based on a mass of the negative electrode material layer, a mass percentage of lanthanum is a, wherein 0.16%≤a≤5%.