Gradient-Resistivity Negative Electrode Plate for Lithium Dendrite Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium dendrites form during the deposition of alkali metals in batteries, leading to safety risks and reducing the cycle life of secondary batteries.
Innovation Solution
A negative-electrode plate with a porous conductive structure and a polymer film layer that has a gradually increasing resistivity from the alkali metal layer surface to the interior, guiding lithium ions to deposit uniformly inside the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous conductive negative electrode is used to replace a conventional negative electrode, then lithium ions can be guided to deposit at more sites and optimize preparation processes, but lithium ions will inevitably gain electrons on the surface and form lithium dendrites
Solution Approach 1:
The polymer film layer is designed with spatially varying conductivity, where the conductivity gradually changes from the surface toward the interior. This local quality variation guides lithium ions to deposit uniformly inside the porous structure rather than concentrating on the surface, preventing dendrite formation while utilizing the high conductivity regions for efficient ion transport.
Solution Approach 2:
The invention changes the conductivity parameter of the polymer film layer from uniform to gradient distributed. By controlling the conductivity distribution parameter, the patent optimizes lithium ion deposition behavior, allowing ions to access multiple sites within the porous structure while preventing surface accumulation that leads to dendrites.
2Productivity
If lithium ions are allowed to deposit on the surface of the porous negative electrode, then deposition occurs at more sites, but accumulation on the surface or between electrodes occurs especially at high current density
Solution Approach 1:
The polymer film layer exhibits local quality variation in conductivity, with higher conductivity near the surface facilitating rapid ion transport, and gradually decreasing conductivity toward the interior guiding uniform distribution. This spatial variation in conductivity quality prevents accumulation at high current densities while maintaining high deposition efficiency.
Solution Approach 2:
The conductivity distribution in the polymer film layer is designed to dynamically adapt to current density conditions. At high current densities, the gradient conductivity structure naturally redirects ion flux to prevent surface accumulation, while at lower current densities, it maintains efficient deposition. This dynamic response ensures uniformity across varying operating conditions.
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
This design prevents lithium dendrite formation by evenly distributing ion deposition, enhancing the cycle life and safety of alkali metal batteries.
Implementation Method 1
surface resistivity of the polymer film layer gradually increases in a thickness direction of the polymer film layer away from the alkali metal layer
Implementation Method 2
lithium ions will inevitably gain electrons on a surface of the negative electrode, thereby forming lithium dendrites
Data Source
AI summary
A negative-electrode plate, a preparation method thereof, and a secondary battery, a battery module, a battery pack, and an electric apparatus including such negative-electrode plate are provided. The negative-electrode plate includes an alkali metal layer and a polymer film layer provided on at least one surface of the alkali metal layer. Surface resistivity of the polymer film layer gradually increases in a thickness direction of the polymer film layer away from the alkali metal layer. When the negative-electrode plate is used in a secondary battery, lithium dendrites can be effectively inhibited.