Lithium Composite Oxide Cathode Material for Suppressing Gas Generation
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in suppressing gas generation during use, which affects their stability and durability, and existing solutions do not adequately address this issue while maintaining cost-effectiveness and performance.
Innovation Solution
A positive electrode active material for lithium ion secondary batteries is developed, comprising lithium composite oxide particles with specific compositions of lithium, nickel, manganese, zirconium, and additive elements, optimized to reduce gas generation by controlling the half-value width of X-ray diffraction peaks and particle size, thereby stabilizing the structure and enhancing cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional positive electrode materials (lithium-cobalt composite oxide, lithium-nickel composite oxide, etc.) are used to achieve high energy density and voltage, then battery energy density and output characteristics are improved, but gas generation occurs due to electrolyte decomposition, worsening battery stability and durability
Solution Approach 1:
The patent changes the compositional parameters of the positive electrode material by incorporating specific ratios of nickel, manganese, and cobalt (with Ni: 0.8-1.2, Mn: 0.1-0.5, Co: 0.05-0.25 in the formula LiaNibMncCooO2), and controlling the half-value width of XRD peaks to 0.055-0.065 degrees. This parameter optimization suppresses electrolyte decomposition while maintaining high energy density.
Solution Approach 2:
The patent creates a composite positive electrode material combining lithium, nickel, manganese, cobalt, and fluorine elements in a specific composite oxide structure (LiaNibMncCooO2). This composite material leverages the high voltage characteristics of nickel-based materials while using manganese and cobalt to suppress gas generation and improve stability.
2Object-generated harmful factors
If additional components are added to battery modules to discharge generated gas to outside the system, then gas discharge function is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent converts the harmful effect of gas generation into a benefit by using fluorine-containing compounds during manufacturing to create a stable surface layer on the positive electrode material. This layer prevents further electrolyte decomposition and gas generation, eliminating the need for additional gas discharge components.
Solution Approach 2:
The patent extracts and eliminates the root cause of gas generation (electrolyte decomposition) by incorporating fluorine into the positive electrode material structure. This prevents the formation of gases that would otherwise require discharge mechanisms, simplifying the overall battery system.
3Ease of manufacture
If the half-value width of XRD peaks is not controlled, then manufacturing process is simpler, but crystal structure stability is insufficient, leading to poor cycle characteristics
Solution Approach 1:
The patent identifies the half-value width of XRD peaks (0.055-0.065 degrees) as a critical parameter that correlates with crystal structure stability. By controlling this parameter during manufacturing, the patent ensures stable cycle characteristics while maintaining manufacturing feasibility through standardized measurement and control procedures.
Data Source
AI summary
A positive electrode active material for a lithium ion secondary battery contains lithium composite oxide particles, the lithium composite oxide particles including lithium (Li), nickel (Ni), manganese (Mn), zirconium (Zr), and an additive element M (M) in an amount of substance ratio of Li:Ni:Mn:Zr:M=a:b:c:d:e, wherein 0.95≤a≤1.20, 0.10≤b<0.70, 0.01≤c≤0.50, 0.0003≤d≤0.02, and 0.01≤e≤0.50, and the additive element M is one or more elements selected from Co, W, Mo, V, Mg, Ca, Al, Ti, and Ta, wherein, a half-value width of a peak of (003) plane calculated from an X-ray diffraction pattern in the lithium composite oxide is 0.055° or more and 0.065° or less.