LiNbO3-Coated High-Nickel Cathode Material for Lower Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High nickel composition NiCoMn-based positive electrode active materials in all-solid lithium ion batteries face increased resistance due to coating with Li and Nb oxides, which is not effectively addressed by existing technologies.
Innovation Solution
A positive electrode active material with a core composition of LiaNibCocMndOe, where 1.0≤a≤1.05, 0.8≤b≤0.9, and 1.8≤e≤2.2, coated with a thin layer of LiNbO3 using an alkoxide solution in a rolling fluidized bed apparatus, optimizing the specific surface area and Nb content to achieve a low-resistance coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer of LiNbO3 is applied to the surface of high nickel composition positive electrode active material, then the formation of high-resistance layer is suppressed, but the resistance increases due to the coating process itself
Solution Approach 1:
The patent optimizes specific surface area (0.3-0.8 m²/g) and Nb content (0.2-0.6 mass%) parameters to balance the protective function of the coating against the resistance increase it causes. By controlling these parameters within specific ranges, the coating suppresses high-resistance layer formation while minimizing resistance increase.
Solution Approach 2:
The patent applies coating selectively to the surface of the positive electrode active material particles, creating a localized protective layer only where needed at the particle surface, rather than throughout the entire material bulk. This ensures protection at the critical interface while minimizing overall resistance impact.
2Manufacturing precision
If the specific surface area is increased to improve coating effectiveness, then the coating coverage is enhanced, but the total Nb content required increases leading to higher resistance
Solution Approach 1:
The patent establishes an optimal relationship between specific surface area (0.3-0.8 m²/g) and Nb content (0.2-0.6 mass%), where the specific surface area is controlled within a moderate range rather than maximized. This balanced approach ensures adequate coating coverage while limiting the total Nb content to prevent excessive resistance increase.
3Use of energy by moving object
If high nickel composition (Ni ratio ≥80 mol%) is used to achieve high capacity, then the energy density is improved, but the resistance increases and coating effectiveness decreases
Solution Approach 1:
The patent maintains high nickel composition (b≥0.8 in formula LiaNibCocMndOe) for high capacity while simultaneously controlling specific surface area (0.3-0.8 m²/g) and Nb content (0.2-0.6 mass%) to manage resistance. This multi-parameter optimization enables high energy density while mitigating the resistance increase associated with high nickel content.
Solution Approach 2:
The patent creates a composite structure combining high nickel composition positive electrode active material (LiNi0.8Co0.1Mn0.1O2) with a LiNbO3 coating layer. This composite approach leverages the high capacity of high nickel material while using the coating to reduce resistance and improve stability.
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 solution results in a low-resistance NiCoMn-based positive electrode active material with improved output characteristics by suppressing the formation of high-resistance layers and reducing diffusion transfer resistance, suitable for high nickel compositions with a Ni ratio of 80 mol % or more.
Implementation Method 1
forming a coating layer consisting of an oxide of Li and Nb on a surface of the core positive electrode active material particle by a rolling fluidized bed apparatus using an alkoxide solution containing Li and Nb
Implementation Method 2
coating with a thin layer of LiNbO3 using an alkoxide solution in a rolling fluidized bed apparatus
Implementation Method 3
by a rolling fluidized bed apparatus using an alkoxide solution containing Li and Nb
Data Source
AI summary
A positive electrode active material for all-solid lithium ion batteries including a core positive electrode active material particle and a coating layer, the core positive electrode active material particle being represented by a composition shown in the following formula (1):LiaNibCocMndOe (1)in which formula (1), 1.0≤a≤1.05, 0.8≤b≤0.9, 1.8≤e≤2.2, b+c+d=1;wherein the coating layer is an oxide of Li and Nb, anda specific surface area X (m2/g) of the positive electrode active material and a Nb content Y (mass %) in the positive electrode active material satisfy a relationship of the following formula (2):0.65≤Y/X≤1.20 (2).