Porous Lithium-Rich Cathode Material for Gas-Stable Capacity
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Solution Overview
Problem
Lithium-rich manganese-based oxides used in positive electrodes of lithium secondary batteries face issues with high resistance, insufficient discharge capacity, and deteriorating life characteristics due to gas generation during the activation process, which affects the structural stability and capacity characteristics.
Innovation Solution
A positive electrode active material comprising a lithium-rich manganese-based oxide with a specific internal porosity range of 2.5% to 13.0%, formed by mixing rock-salt-type lithium manganese oxide and layered lithium transition metal oxide, is prepared through a co-precipitation reaction and firing process, enhancing electrolyte penetration and reducing particle cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-rich manganese-based oxide is used as positive electrode active material, then high energy density and capacity characteristics are achieved, but resistance increases and discharge capacity becomes insufficient
Solution Approach 1:
The patent applies porous materials by controlling the internal porosity of lithium-rich manganese-based oxide particles to 2.5% to 13.0%. This porous structure increases the surface area for electrolyte contact, improves lithium ion diffusion pathways, and reduces electrode resistance, thereby enhancing discharge capacity while maintaining high energy density.
Solution Approach 2:
The patent uses composite materials by creating a mixed structure of rock-salt-type lithium manganese oxide and layered lithium transition metal oxide within the same particle. This composite structure combines the high capacity characteristics of lithium-rich manganese oxide with the structural stability and conductivity of layered phases, resolving the contradiction between energy density and discharge capacity.
2Quantity of substance
If rock-salt phase is activated to generate excess lithium ions, then capacity characteristics improve, but gas generation occurs causing electrode deterioration and reduced life characteristics
Solution Approach 1:
The patent converts the harmful gas generation during rock-salt phase activation into a beneficial effect by controlling internal porosity to 2.5% to 13.0%. The porous structure provides pathways for gas release that prevent electrode deterioration, while the same porosity enhances lithium ion generation from the rock-salt phase, transforming a harmful process into a beneficial one.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the internal porosity parameter within 2.5% to 13.0% to optimize the balance between lithium ion generation and gas management. This parameter control allows the rock-salt phase activation to proceed effectively while minimizing harmful gas accumulation and electrode deterioration.
3Reliability
If internal porosity is increased to improve electrolyte penetration, then discharge capacity improves, but particle structural stability may deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing internal porosity within the specific range of 2.5% to 13.0%. This controlled porosity level is sufficient to improve electrolyte penetration and discharge capacity while maintaining enough structural integrity to prevent particle cracking and deterioration during battery cycling.
Solution Approach 2:
The patent uses composite materials where the layered lithium transition metal oxide phase provides structural stability to the particle framework, while the rock-salt phase within the porous structure contributes to high capacity. This composite approach allows the particle to maintain structural integrity even with controlled internal porosity.
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 material exhibits improved discharge capacity and life characteristics by optimizing the contact state between particles, suppressing gas generation and side reactions, and maintaining structural integrity during charge and discharge cycles.
Implementation Method 1
the positive electrode and the negative electrode include an active material capable of intercalation and deintercalation of lithium ions
Implementation Method 2
formed by mixing rock-salt-type lithium manganese oxide and layered lithium transition metal oxide, is prepared through a co-precipitation reaction and firing process
Implementation Method 3
is prepared through a co-precipitation reaction and firing process
Data Source
AI summary
A positive electrode active material includes a lithium-rich manganese-based oxide represented by the following Chemical Formula 1, and has a structure in which a rock-salt-type lithium manganese oxide and a layered lithium transition metal oxide are mixed. The lithium-rich manganese-based oxide may have a prescribed internal porosity.in Chemical Formula 1, 1.00<a, 0≤b≤0.53, 0≤c≤0.10, 0.47≤d≤1.00, 0≤e≤0.20, and M is at least one selected from the group consisting of Al, B, Co, W, Mg, V, Ti, Zn, Ga, In, Ru, Nb, Sn, Sr and Zr.