High-Ni Cathode Active Material With Al-Sr Layer Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positive electrode active materials for non-aqueous electrolyte secondary batteries with high Ni content and low Co content face instability in layered structure, leading to increased reaction resistance.
Innovation Solution
Incorporating specific proportions of Al and Sr into the lithium composite oxide, along with other metal elements, stabilizes the layered structure and reduces reaction resistance by maintaining the Li layer integrity during charge/discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the proportion of Ni is increased to 85 mol% or more and Co is reduced to 10 mol% or less, then the production cost is reduced and discharge capacity is increased, but the layered structure becomes unstable and reaction resistance increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of metal elements in the lithium composite oxide. Specifically, it sets Ni proportion at 85-95 mol%, Co at 5-15 mol%, and introduces Sr at 0.01-0.05 mol% with a Mo/Sr ratio of 0.5-2.0. These parameter optimizations maintain layered structure stability while achieving high capacity and low cost by maximizing Ni content and minimizing Co content.
Solution Approach 2:
The patent employs composite materials by creating a multi-element lithium composite oxide system combining Li, Ni, Co, Sr, and Mo. This composite approach leverages the high capacity of Ni, the structural stability contribution of Co, the stabilizing effect of Sr in the layered structure, and the synergistic interaction between Mo and Sr. The composite material design resolves the contradiction by integrating multiple functional elements that collectively maintain stability while enabling high Ni content.
2Quantity of substance
If the proportion of Ni is increased to 85 mol% or more, then the discharge capacity is increased, but the layered structure becomes unstable and reaction resistance increases
Solution Approach 1:
The patent optimizes parameter changes by setting Ni proportion within 85-95 mol% range, which maximizes discharge capacity while preventing excessive Ni content from causing structural instability. The controlled composition parameters including Co (5-15 mol%), Sr (0.01-0.05 mol%), and Mo/Sr ratio (0.5-2.0) work synergistically to maintain layered structure stability at high Ni concentrations.
Solution Approach 2:
The patent introduces Sr as an intermediary element that mediates between high Ni content and structural stability. Sr acts as a stabilizing agent in the layered structure, preventing the degradation that would otherwise occur at high Ni proportions. The Mo/Sr interaction further enhances this stabilizing effect, allowing the system to achieve high capacity through high Ni content while maintaining structural integrity.
3Ease of manufacture
If the Co content is reduced to minimize production cost, then the production cost is reduced, but the layered structure stability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing Co content to 5-15 mol%, which is lower than conventional compositions, thereby reducing production cost. Simultaneously, it introduces Sr at 0.01-0.05 mol% and controls the Mo/Sr ratio to 0.5-2.0, which compensates for the reduced Co content and maintains layered structure stability through the stabilizing effect of Sr and its interaction with Mo.
Solution Approach 2:
The patent effectively replaces part of the structural stabilizing function of Co with Sr and Mo. By introducing Sr as a substitute stabilizing element and leveraging the synergistic Mo-Sr interaction, the system copies or replicates the structural stability function that would otherwise be provided by higher Co content, thereby enabling cost reduction through lower Co while maintaining stability.
Data Source
Figure 1
AI summary
Provided is a cathode active material for a non-aqueous-electrolyte secondary battery, the cathode active material containing a lithium composite oxide that has a layered structure containing a Li layer and that is represented by general formula LiaNiαAlβCoγMδSrxO2-w (in the formula, 0.95 < a < 1.05, 0.85 ≤ α ≤ 0.95, 0 < β ≤ 0.08, 0 ≤ γ ≤ 0.1, 0 ≤ δ ≤ 0.15, 0 < x ≤ 0.015, 0 ≤ w < 0.05, α + β + γ + δ = 1, and M is at least one type of element selected from Mn, Fe, Ti, Si, Nb, Zr, Mo, and Zn), wherein the proportions of metal elements present in the Li layer excluding Li are in the range of 1-2.5 mol% with respect to the total molar quantity of metal elements in the lithium composite oxide excluding Li.