Lithium Battery Cathode Composition for Power-Life Balance
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving a balance between high power, capacity, and life-span properties, as cathode active materials designed for high power degrade life-span, and those designed for long life-span compromise electrical properties.
Innovation Solution
A cathode composition comprising a combination of first and second cathode active material particles with specific chemical formulations and shapes, along with a conductive material, including linear-type carbon nanotubes, to enhance stability and conductivity, thereby improving power, capacity, and life-span retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the cathode active material is designed to have a high-power/capacity composition, then power and capacity are improved, but life-span property is degraded
Solution Approach 1:
The cathode active material uses a composite structure combining LiNi0.8Co0.1Mn0.1O2 (high power) and LiCo0.8Ni0.1Mn0.1O2 (high capacity) materials, achieving both high power and long life-span through material composition optimization
Solution Approach 2:
The patent optimizes the ratio of high-power material to high-capacity material within 95:5 to 5:95, and controls particle size distribution (D50: 3-10 μm, D90: 15-30 μm) to balance power output and life-span durability
2Duration of action of stationary object
If the cathode active material is designed to have an enhanced life-span composition, then life-span property is improved, but electrical properties are degraded
Solution Approach 1:
The dual-material composite structure combines materials with different properties: LiNi0.8Co0.1Mn0.1O2 for power and LiCo0.8Ni0.1Mn0.1O2 for stability, achieving both long life-span and good electrical properties through synergistic combination
Solution Approach 2:
By controlling the weight ratio of the two materials and particle size distribution, the patent achieves optimal balance between life-span and electrical properties without using excessive conductive additives
3Quantity of substance
If a transition metal compound and ion adsorption binder are used as cathode active material, then capacity is achieved, but power and life-span properties are insufficient
Solution Approach 1:
The patent replaces conventional ion adsorption binders with a dual-material composite cathode active material, achieving superior power and life-span properties while maintaining high capacity through the synergistic effect of LiNi0.8Co0.1Mn0.1O2 and LiCo0.8Ni0.1Mn0.1O2
Solution Approach 2:
The invention changes from using binder materials to using a composite cathode active material structure, optimizing the composition ratio and particle size to simultaneously achieve high capacity, power, and life-span properties
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 cathode composition achieves improved stability, reduced resistance, and enhanced high-temperature stability while maintaining sufficient power and capacity, as evidenced by the reduced crack formation and increased crystallinity, leading to a more reliable lithium secondary battery performance.
Implementation Method 1
a conductive material including a linear-type conductive material
Implementation Method 2
a peak intensity ratio of a Raman spectrum of the conductive material defined as Equation 1 may be in a range from 0.8 to 1.25
Data Source
AI summary
Lithium secondary batteries for improving life span and resistance properties are disclosed. In an aspect, a cathode composition for a lithium secondary battery includes a cathode active material that includes a first cathode active material particle having a secondary particle shape and a second cathode active material particle having a single particle shape, and a conductive material including a linear-type conductive material.