Composite Cathode Active Material for High-Density Li-Ion Batteries
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, and high charge-discharge efficiency while maintaining a long lifespan.
Innovation Solution
A positive electrode active material comprising a mixture of first and second particles, where the first particle is an olivine-based lithium compound with specific doping, and the second particle is a lithium nickel-based composite oxide, combined in a specific ratio to enhance conductivity and structural stability, resulting in improved energy density and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single positive electrode active material is used, then the battery structure is simple, but it is difficult to achieve high energy density, high operating voltage, and long lifespan simultaneously
Solution Approach 1:
The patent applies composite materials by combining two distinct positive electrode active materials: an olivine-based lithium compound (LiMn0.5Fe0.5PO4 with Mg and Ti doping) and a lithium nickel-based composite oxide (LiNi0.6Co0.1Mn0.3O2). This composite structure enables the battery to achieve high energy density, high operating voltage, and long lifespan simultaneously by leveraging the complementary properties of both materials - the olivine compound provides structural stability and safety while the nickel-based oxide contributes high capacity and voltage
Solution Approach 2:
The patent segments the positive electrode active material into two distinct particle types with different compositions, sizes, and functions. The first particles (olivine-based) have a specific size range and composition optimized for structural stability, while the second particles (nickel-based) have different characteristics optimized for capacity. This segmentation allows each material to perform its specialized function within the composite electrode
2Productivity
If high capacity materials are used to increase energy density, then operating voltage and capacity improve, but charge-discharge efficiency and lifespan deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios and particle size distributions of the two active materials. The olivine-based compound uses specific doping levels (Mg: 0.01-0.05 mol, Ti: 0.01-0.05 mol) and particle size (3-6 μm), while the nickel-based oxide has controlled composition (LiNi0.6Co0.1Mn0.3O2) and particle size (6-12 μm). These parameter optimizations ensure high capacity while maintaining good charge-discharge efficiency and cycle life
3Productivity
If high capacity materials are used to increase energy density, then capacity improves, but structural stability and lifespan worsen
Solution Approach 1:
The patent uses composite materials where the olivine-based lithium compound (LiMn0.5Fe0.5PO4) serves as a structurally stable framework with proven long-term stability, while the lithium nickel-based composite oxide (LiNi0.6Co0.1Mn0.3O2) provides high capacity. The two materials work synergistically, with the stable olivine structure compensating for the lower intrinsic stability of the nickel-based material, thereby achieving both high capacity and long lifespan
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 combined particles achieve high energy density, high operating voltage, and high charge-discharge efficiency with a long lifespan, offering improved capacity retention and reduced binder usage, leading to enhanced battery performance.
Implementation Method 1
a rechargeable lithium battery typically includes a positive electrode and a negative electrode containing an active material capable of intercalation and deintercalation of lithium ions
Implementation Method 2
Electrical energy is produced by oxidation and reduction reactions when the lithium ions are intercalated and deintercalated into/from the positive electrode and the negative electrode
Data Source
AI summary
Examples of the disclosure include a positive electrode active material for a rechargeable lithium battery, a positive electrode including the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material. Examples of the disclosure include a positive electrode active material including a first particle containing a compound having a first average particle diameter, and a second particle containing a compound having a second average particle diameter larger than the first average particle diameter.