Layered Oxide Cathode Particles With Porosity for Lower Resistance
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Solution Overview
Problem
Existing positive electrode active materials for lithium ion secondary batteries have room for improvement in output characteristics, necessitating the development of a material that can enhance reaction area with the electrolyte and reduce internal resistance.
Innovation Solution
A positive electrode active material composed of lithium transition metal-containing composite oxide particles with a specific composition and structure, including a layered rock salt type crystal structure, secondary particles with a controlled particle size distribution, and a unique pore structure, which enhances the contact area with the electrolyte and promotes lithium ion insertion and de-insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If particles having a small particle size are used as positive electrode active material, then reaction area with electrolyte is increased and positive electrode resistance is reduced, but manufacturing precision and particle size control become more difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling particle size parameters (d50 between 3.0-7.0 μm, specific surface area between 1.8-5.5 m2/g) and pore structure parameters (pore peak diameter 0.01-0.30 μm, log differential pore volume 0.2-0.6 ml/g) to achieve optimal balance between reaction area and manufacturing feasibility. This systematic parameter optimization resolves the contradiction by establishing specific numerical ranges that simultaneously satisfy both improved reaction area and controllable manufacturing precision.
2Power
If internal resistance is reduced to improve output characteristics, then battery output is increased, but particle size and structure control becomes more complex
Solution Approach 1:
The patent introduces a porous structure with specific characteristics (pore peak diameter 0.01-0.30 μm, log differential pore volume 0.2-0.6 ml/g) into the positive electrode active material. This porous structure increases the reaction area with electrolyte and reduces internal resistance, thereby improving output characteristics without requiring excessive complexity in particle size control. The porous structure acts as an intrinsic feature that naturally enhances performance while maintaining manageable manufacturing complexity.
3Reliability
If particle size distribution is narrowed to improve voltage uniformity, then selective degradation of fine particles is suppressed, but manufacturing flexibility is reduced
Solution Approach 1:
The patent applies parameter changes by defining a specific particle size distribution range (d50: 3.0-7.0 μm, with d90-d10)/d50 ≤ 1.0) that ensures voltage uniformity across particles during battery operation. This controlled parameter range suppresses selective degradation of fine particles and improves cycle characteristics, while still allowing sufficient manufacturing flexibility for industrial production. The parameter optimization balances reliability improvement with manufacturing adaptability.
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 positive electrode active material significantly improves the output characteristics of lithium ion secondary batteries by increasing the reaction area with the electrolyte and reducing internal resistance, leading to higher energy density and longer cycle life.
Implementation Method 1
as an active material used as a material for these negative electrode and positive electrode, a material capable of de-inserting and inserting lithium is used
Data Source
AI summary
A positive electrode active material is constituted by lithium transition metal-containing composite oxide particles having a layered rock salt type crystal structure and are composed of secondary particles each formed of an aggregation of primary particles. The secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 1.8 to 5.5 m2/g, a pore peak diameter of 0.01 to 0.30 μm, and a log differential pore volume [dV/d(log D)] of 0.2 to 0.6 ml/g within a range of the pore peak diameter. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less.