Composite Anode Material for Fast-Charge Dendrite Suppression
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Solution Overview
Problem
Lithium-ion batteries face issues with lithium dendrite formation during fast charging, leading to macroscopic lithium plating, micro-short circuits, and reduced battery performance.
Innovation Solution
A composite material is developed for the negative electrode of lithium-ion batteries, comprising a negative electrode active material, dielectric material particles, and a binder, where the dielectric material particles are bridged to the binder via a coupling agent, enhancing their dispersion and bonding with the active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dielectric material particles are added to improve fast charge performance, then desolvation barrier is reduced and fast charge performance is improved, but particle dispersion uniformity deteriorates and particles settle at the bottom of slurry
Solution Approach 1:
A coupling agent is introduced as an intermediary substance between the dielectric material particles and the binder. The coupling agent contains functional groups that react with both the particle surface and the binder, creating a stable bridge that prevents particle aggregation and settling while maintaining uniform dispersion in the slurry.
Solution Approach 2:
The patent creates a composite structure where dielectric material particles are chemically bonded to the binder through coupling agents. This composite material combines the fast charge enhancement properties of dielectric particles with the binding and dispersing properties of the modified binder system.
2Reliability
If dielectric material particles are used to modify negative electrode, then modification effect is enhanced, but bonding strength between particles and active material deteriorates
Solution Approach 1:
The coupling agent serves as a mediator that chemically connects dielectric material particles to the binder and active material. This intermediary substance provides anchoring functional groups that strengthen the bonding interface while allowing the dielectric particles to maintain their modification function.
Solution Approach 2:
The coupling agent is applied specifically at the interface between dielectric particles and the binder/active material, providing localized bonding enhancement where it is most needed, while leaving the bulk properties of the particles and active material unchanged.
3Ease of manufacture
If conventional electrode material is used, then manufacturing process is simple, but lithium dendrite formation occurs during fast charging leading to micro-short circuits
Solution Approach 1:
The patent develops a composite negative electrode material combining conventional active materials with dielectric material particles. This composite structure maintains manufacturability similar to conventional electrodes while adding the functionality of reduced desolvation barriers and improved lithium ion transport that prevents dendrite formation.
Solution Approach 2:
The dielectric material particles create a modified interface that converts the harmful concentration gradient effects into beneficial uniform lithium ion distribution. The particles generate local electric fields that promote uniform desolvation and prevent the accumulation of lithium ions that would otherwise lead to dendrite formation.
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 composite material improves the negative electrode capacity, first-week coulombic efficiency, reduces charging resistance, and extends the cycle life of lithium-ion batteries.
Implementation Method 1
a coupling agent that bridges the dielectric material particle and the binder
Implementation Method 2
A high dielectric-constant material, of which the dielectric constant is similar to that of an electrolyte solution, is beneficial to reduce a desolvation barrier
Data Source
AI summary
The present application provides a composite material, comprising: a negative electrode active material, a dielectric material particle and a binder resin; wherein at least a part of a surface of the dielectric material particle is covered with a coupling agent that bridges the dielectric material particle and the binder resin.