Block Copolymer Metal Electrode Coating for Dendrite Suppression
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Solution Overview
Problem
The uneven deposition of metal dendrites on the surface of metal electrodes in batteries leads to performance attenuation and failure, and existing coatings either increase impedance or fail to inhibit dendrite growth effectively.
Innovation Solution
A metal electrode with a coating comprising a block copolymer that includes a first polymer block for conducting metal ions and a second polymer block for mechanical strength, with a shear modulus of ≥107 Pa and a thickness of 500 nm-50 μm, forming a uniform ion transmission channel and inhibiting dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to inhibit lithium dendrite, then dendrite growth is suppressed, but interface impedance increases and ion conductivity decreases
Solution Approach 1:
The patent employs a block copolymer coating composed of two distinct polymer blocks: a first block (polymer A) with high lithium ion conductivity to reduce interface impedance, and a second block (polymer B) with high mechanical strength and shear modulus (≥107 Pa) to inhibit dendrite growth. This composite structure allows the coating to simultaneously achieve both dendrite suppression and low impedance by combining materials with complementary properties.
Solution Approach 2:
The block copolymer coating exhibits local quality differentiation where different regions (polymer blocks) possess different functional properties. The first polymer block provides ion conduction pathways with low impedance, while the second polymer block provides mechanical reinforcement for dendrite inhibition. This spatial differentiation of functions within the coating enables simultaneous optimization of both ion transport and structural stability.
2Reliability
If embedded negative electrode materials like graphite are used to improve safety, then safety performance is enhanced, but energy density decreases
Solution Approach 1:
The block copolymer coating acts as an intermediary protective layer between the high-capacity lithium metal negative electrode and the electrolyte. This intermediate coating enables the use of lithium metal (which has 3860 mAh/g theoretical specific capacity, much higher than graphite) by preventing dendrite growth and ensuring stable interface, thus achieving both high energy density and safety performance simultaneously.
3Reliability
If fluoropolymer with -SO3Y functional group is used as coating, then component stability is improved, but ionic conductivity decreases and cost increases
Solution Approach 1:
The patent changes the chemical and physical parameters of the coating material by using block copolymer architecture instead of conventional fluoropolymer. The first polymer block is specifically designed with high lithium ion conductivity (≥10−6 S/cm at 80°C), which is achieved by selecting polymer chains with appropriate side groups and spacing that facilitate ion transport, while the second block provides mechanical stability.
4Reliability
If block polymer is used as solid electrolyte to inhibit dendrite, then dendrite growth is suppressed, but internal resistance increases and adhesion to electrode is poor
Solution Approach 1:
The coating is segmented into two functional blocks: the first block (polymer A) with high ion conductivity to reduce internal resistance and improve adhesion to the metal electrode, and the second block (polymer B) with high mechanical strength for dendrite suppression. This segmentation allows each block to optimize its specific function without compromising the other, unlike using a single block polymer as solid electrolyte.
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 coating enhances ion conductivity and mechanical stability, reducing interface impedance and improving discharge capacity and cycle performance by preventing dendrite formation, thus extending battery life and maintaining stable charge-discharge cycles.
Implementation Method 1
a first polymer block for independently conducting metal ions
Implementation Method 2
a second polymer block for providing mechanical strength; a shear modulus of the coating is ≥107 Pa
Data Source
AI summary
In order to overcome the problem of metal dendrites caused by uneven deposition on the surface of the existing metal electrode, the present application provides a metal electrode, comprising a metal layer and a coating, the coating comprises at least one block copolymer; the block copolymer comprises a first polymer block for independently conducting metal ions and a second polymer block for providing mechanical strength; a shear modulus of the coating is ≥107 Pa, and a thickness of the coating is 500 nm-50 μm. Meanwhile, the application also discloses a battery comprising the metal electrode. The metal electrode provided by the application has good ionic conductivity and inhibition capability for metal dendrite.