Segmented Lithium Composite Oxide Electrode for Gas Suppression
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges in achieving high capacity and high power while minimizing gas generation during charging/discharging cycles at high temperatures.
Innovation Solution
A positive electrode active material comprising a combination of lithium composite oxide A containing W and Ni, and W-free lithium composite oxide B containing Ni, with specific particle size distributions and mass ratios, is used to enhance battery performance and reduce gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium composite oxides with different particle sizes and compositions are used to improve battery capacity and power, then high capacity and high power are achieved, but gas generation during charging/discharging cycles at high temperatures increases
Solution Approach 1:
The positive electrode active material is segmented into two distinct types: lithium composite oxide A (finer particles, 2-6 μm D50, containing W and Ni) and lithium composite oxide B (coarser particles, 10-22 μm D50, W-free, containing Ni). This segmentation allows each component to fulfill specific functions - oxide A provides high power and capacity while oxide B suppresses gas generation, resolving the contradiction between productivity and harmful factors
Solution Approach 2:
Different regions of the particle size distribution are assigned different compositions and functions. The finer oxide A particles (2-6 μm) with W and Ni content are optimized for electrochemical activity and capacity, while the coarser oxide B particles (10-22 μm) without W are optimized for structural stability and gas suppression. This local quality differentiation enables simultaneous achievement of high capacity/power and low gas generation
2Power
If lithium composite oxide with high Ni content is used to improve battery power, then high power is achieved, but gas generation during charging/discharging cycles at high temperatures increases
Solution Approach 1:
The Ni-containing lithium composite oxide is segmented into two compositional types: oxide A containing both W and Ni (30-60 mol% Ni) for high power, and oxide B containing Ni without W (50-95 mol% Ni) for gas suppression. The mass ratio control (1:1 to 5.7:1) ensures optimal balance between power delivery and gas generation suppression
Solution Approach 2:
The positive electrode active material is a composite system combining two types of lithium composite oxides with complementary properties. Oxide A (with W) provides high power characteristics while oxide B (W-free) provides gas suppression, creating a composite material that achieves both high power and low gas generation simultaneously
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 combination of lithium composite oxides with specific particle sizes and compositions enables high-capacity, high-power batteries while effectively suppressing gas generation during high-temperature charging/discharging cycles.
Implementation Method 1
nonaqueous electrolyte secondary batteries including a positive electrode, a negative electrode, and a nonaqueous electrolyte, which are charged and discharged by transfer of, for example, lithium ions between the positive electrode and the negative electrode
Data Source
AI summary
The positive electrode active material with lithium composite oxide A containing W and Ni and W-free lithium composite oxide B containing Ni. Regarding the lithium composite oxide A, the proportion of Ni relative to the total moles of metal elements except for lithium is 30 to 60 mol %, 50% particle size D50 is 2 to 6 μm, 10% particle size D10 is 1.0 μm or more, and 90% particle size D90 is 6.8 μm or less. Regarding the lithium composite oxide B, the proportion of Ni relative to the total moles of metal elements except for lithium is 50 to 95 mol %, 50% particle size D50 is 10 to 22 μm, 10% particle size D10 is 7.0 μm or more, and 90% particle size D90 is 22.5 μm or less. The mass ratio of the lithium composite oxide B to the lithium composite oxide A is 1:1 to 5.7:1.