Rolled Aluminum Anode Microstructure for Better Battery Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metal anodes made of aluminum have improved theoretical capacity but suffer from deteriorating cycle characteristics, which are essential for the long-term performance of lithium secondary batteries as they degrade with repeated charging and discharging.
Innovation Solution
An anode active material is developed with an aluminum-containing metal where a non-aluminum phase is dispersed within an aluminum phase, specifically rolled in one direction, with controlled crystal grain sizes and aspect ratios, and containing elements like Ti, B, and Si, to enhance cycle characteristics by reducing stress and cracking during lithium intercalation and deintercalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a metal anode made of aluminum is used, then the theoretical capacity is improved, but the cycle characteristics deteriorate
Solution Approach 1:
The invention uses a composite material structure where an aluminum-based alloy contains a non-aluminum phase dispersed within the aluminum phase. This composite structure allows the anode to achieve high theoretical capacity from the aluminum while the dispersed non-aluminum phase prevents cracking and maintains structural integrity during cycling, thus improving cycle characteristics
Solution Approach 2:
The invention applies local quality by creating regions with different properties within the aluminum anode. The non-aluminum phase is distributed at specific locations (grain boundaries or dispersed throughout) to provide local reinforcement and stress relief, while the majority aluminum phase maintains high lithium ion capacity. This localized modification solves the contradiction between overall capacity and local structural stability
2Reliability
If the crystal grain size is reduced to improve cycle characteristics, then the manufacturing precision requirements increase
Solution Approach 1:
The invention changes the material composition parameters by adding specific elements (Ti: 10-1000 mass ppm, B: 2-200 mass ppm) to the aluminum alloy. These compositional changes naturally influence the crystal grain growth during solidification and rolling processes, achieving fine grain structure (average grain diameter 4.5 μm or less) through controlled alloying rather than extreme mechanical processing, thus reducing manufacturing precision requirements
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 proposed anode active material significantly improves the cycle characteristics of lithium secondary batteries by maintaining discharge capacity retention rates, thereby extending the battery's lifespan and performance.
Implementation Method 1
a non-aluminum phase is dispersed in an aluminum phase... to enhance cycle characteristics by reducing stress and cracking during lithium intercalation and deintercalation
Implementation Method 2
a material having a larger theoretical capacity than graphite... a metal material capable of absorbing and releasing lithium ions
Data Source
AI summary
This anode active material for a lithium secondary battery is an aluminum-containing metal in which a non-aluminum phase is dispersed in an aluminum phase, the aluminum-containing metal is a rolled material rolled in one direction, and the non-aluminum phase contains any one or both of B and Ti and satisfies the following (1) and (2) in an image acquired by a method described in the following image acquisition conditions.