Capacitor-Assisted Gradient Electrode for Lithium Plating Control
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Solution Overview
Problem
Conventional lithium-ion batteries face limitations in regeneration capabilities, particularly during high power and frequent charging processes, due to lithium plating on electrode surfaces, which can lead to reduced performance and increased material costs for certain materials like hard carbon.
Innovation Solution
The development of capacitor-assisted gradient electrodes, where multiple electroactive materials with varying specific capacities and densities are integrated with capacitor materials on current collectors, enhancing lithium intercalation and de-intercalation rates and regeneration capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion battery electrodes are used, then the battery can operate and provide basic energy storage, but the regeneration capabilities are limited during high power and frequent charging processes due to lithium plating on electrode surfaces
Solution Approach 1:
The patent applies local quality by creating a gradient electrode structure where the composition varies spatially. The electrode includes a first region with a first composition and a second region with a second composition, where the compositions differ in their lithium intercalation/deintercalation properties. This gradient structure allows different regions to handle different aspects of lithium ion transport, with some regions optimized for fast charging (lower lithium content) and others for capacity (higher lithium content), thereby reducing lithium plating at the surface during high-power regeneration while maintaining overall battery capacity.
2Reliability
If hard carbon material is used to improve regeneration capabilities and minimize plating, then the performance improves, but the material cost increases
Solution Approach 1:
The patent applies parameter changes by varying the lithium content parameter across different regions of the electrode. The first region has a first lithium content and the second region has a second lithium content, creating a gradient in this critical parameter. This allows the electrode to achieve improved regeneration capability in regions with lower lithium content while maintaining overall capacity through regions with higher lithium content, avoiding the need to use expensive hard carbon material throughout the entire electrode structure.
3Ease of manufacture
If the electrode structure is simplified, then the manufacturing process is easier, but the lithium transfer channels and distribution cannot be optimized for high-power regeneration
Solution Approach 1:
The patent applies segmentation by dividing the electrode into distinct regions with different compositions. The electrode is segmented into a first region and a second region, each with specific compositional characteristics. This segmentation allows for optimized lithium transfer channels in each region while maintaining a manageable manufacturing process, as the gradient structure can be created through controlled deposition or coating techniques during electrode fabrication.
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 approach improves the high-power regeneration capabilities and durability of lithium-ion batteries by optimizing lithium transfer channels and distribution, reducing lithium content deviation, and minimizing dendrite formation, while potentially lowering material costs.
Implementation Method 1
One or more capacitor materials may be disposed on or intermingled with one or more of the at least two electroactive materials
Implementation Method 2
Concurrent to this, electrons pass through an external circuit from the negative electrode to the positive electrode. Such lithium ions may be incorporated into the material of the positive electrode by an electrochemical reduction reaction
Data Source
AI summary
A capacitor-assisted electrode for an electrochemical cell that cycles lithium ions is provided. The capacitor-assisted electrode may include at least two electroactive materials disposed on one or more surfaces of a current collector. A first electroactive material of the at least two electroactive materials may have a first reversible specific capacity and forms a first electroactive material having a first press density. A second electroactive material of the at least two electroactive materials has a second reversible specific capacity and forms a second electroactive material having a second press density. The second reversible specific capacity may be different from the first reversible specific capacity. The second press density may be different from the first press density. One or more capacitor materials may be disposed on or intermingled with one or more of the at least two electroactive materials.