Layered-Olivine Positive Electrode Structure for Fast-Charging Capacity
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density and capacity, particularly in optimizing the positive electrode structure for improved charge/discharge characteristics.
Innovation Solution
A multi-layered positive electrode structure is introduced, comprising a first layer with a layered positive electrode active material and a second layer with an olivine-based active material, both featuring strategically designed holes to enhance lithium ion transfer and stability, along with specific coating layers to improve structural integrity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-layer positive electrode active material is used, then the electrode structure is simple, but the charge/discharge performance and capacity are limited
Solution Approach 1:
The positive electrode active material layer is divided into two distinct layers: a first layer containing layered positive electrode active material and a second layer containing olivine-based positive electrode active material. Each layer contributes different electrochemical properties, with the layered material providing high capacity and the olivine-based material providing structural stability, thereby improving overall charge/discharge performance while maintaining a manageable two-layer structure.
Solution Approach 2:
The patent combines two different types of positive electrode active materials (layered and olivine-based) into a composite multi-layered structure. This composite approach leverages the advantages of both material types: the layered material offers high lithium ion capacity while the olivine-based material provides structural stability and fast ion transport, resulting in superior overall performance compared to single-material electrodes.
2Speed
If holes are formed in the positive electrode active material layer, then lithium ion transfer is enhanced, but the structural integrity may be compromised
Solution Approach 1:
Holes are formed at specific locations within the positive electrode active material layers to create localized pathways for lithium ion transport. The holes are strategically positioned to enhance ion transfer efficiency without compromising the overall structural integrity of the electrode. This localized modification allows rapid charge/discharge performance while maintaining sufficient mechanical strength.
3Quantity of substance
If high nickel content is used in layered positive electrode active material, then capacity increases, but structural stability decreases
Solution Approach 1:
The patent combines high-nickel layered positive electrode active material (providing high capacity) with olivine-based positive electrode active material (providing structural stability). The layered material contributes high lithium ion capacity due to its high nickel content, while the olivine-based material compensates for structural instability through its inherently stable framework, achieving both high capacity and structural stability in the composite electrode.
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 multi-layered structure enhances charge/discharge performance, leading to improved capacity and energy density, while maintaining structural stability and rapid charge characteristics.
Implementation Method 1
the positive and negative electrodes include an active material in which intercalation and deintercalation are possible, and the rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions when lithium ions are intercalated and deintercalated
Implementation Method 2
the rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions when lithium ions are intercalated and deintercalated
Implementation Method 3
The first positive electrode active material layer may include a plurality of first holes. The second positive electrode active material layer may include a plurality of second holes
Data Source
AI summary
Examples of the disclosure include positive electrodes, manufacturing methods thereof, and rechargeable lithium batteries. The positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer includes a first positive electrode active material layer and a second positive electrode active material layer that are stacked on the positive electrode current collector. The first positive electrode active material layer includes a layered positive electrode active material. The second positive electrode active material layer includes an olivine-based positive electrode active material. The first positive electrode active material layer includes first holes. The second positive electrode active material layer includes second holes.