Cathode Material Pore Distribution for Stable Li-Ion Capacity
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Solution Overview
Problem
Existing lithium-ion battery cathode materials face challenges in balancing short-term and long-term properties due to issues with pore diameter distribution and surface crystal structure stability, leading to decreased capacity and shortened service life.
Innovation Solution
A cathode material with specific pore diameter distribution, microcrystallite structure, and controlled pH during preparation processes to achieve optimal short-term and long-term performance, including a composition of Li(Ni1-x-y-z-mCoxMyGzHz)O2 with controlled sintering and cladding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel oxyfluoride is used as positive electrode material, then battery capacity is improved, but material stability deteriorates due to Jahn-Teller distortion
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties from the core. The surface is modified with lithium nickel oxyfluoride phase having specific stoichiometry (Li:Ni:O:F ratio) that differs from the bulk, providing local structural stability while maintaining the high-capacity bulk composition. This local modification at the surface prevents Jahn-Teller distortion without compromising the overall battery capacity.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel oxyfluoride with other phases to form a multi-phase composite structure. The positive electrode material comprises a composite of lithium nickel oxyfluoride phase and additional phases that provide structural stability. This composite approach allows the material to benefit from the high capacity of lithium nickel oxyfluoride while the other phases compensate for its instability through synergistic effects.
2Stability of the object's composition
If conventional positive electrode materials are used, then material stability is maintained, but battery capacity is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the stoichiometric ratios and phase composition of the positive electrode material. Specifically, it adjusts the Li:Ni:O:F ratio and controls the formation of lithium nickel oxyfluoride phase with specific parameters (crystal structure, surface area, phase purity) to achieve both high capacity and stability. The method also controls particle size and surface area parameters to optimize performance.
3Power
If lithium nickel oxyfluoride is utilized, then battery output is enhanced, but material instability increases due to Jahn-Teller distortion
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties from the core. The surface is modified with lithium nickel oxyfluoride phase having specific stoichiometry (Li:Ni:O:F ratio) that differs from the bulk, providing local structural stability while maintaining the high-capacity bulk composition. This local modification at the surface prevents Jahn-Teller distortion without compromising the overall battery capacity.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel oxyfluoride with other phases to form a multi-phase composite structure. The positive electrode material comprises a composite of lithium nickel oxyfluoride phase and additional phases that provide structural stability. This composite approach allows the material to benefit from the high capacity of lithium nickel oxyfluoride while the other phases compensate for its instability through synergistic effects.
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 cathode material enhances both initial charge-discharge capacity and cycle performance by regulating surface impedance and preventing surface collapse, thereby extending battery life and maintaining capacity retention.
Implementation Method 1
a positive electrode material for lithium ion battery and a preparation method therefor and use thereof, and lithium ion battery
Data Source
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AI summary
The present invention relates to the field of lithium ion battery positive electrode materials, and discloses a positive electrode material, a preparation method therefor, a use thereof, and a lithium ion battery. The positive electrode material is formed by agglomerating primary particles to form secondary particles; and by means of BJH, the secondary particles obtain phase apertures d10, dso and d90 that meet the following phase system: 10nm≤d50≤40nm; 1≤k90≤8; wherein k90=(d90-d10)/d50. The positive electrode has a specific apertures, apertures distribution, apertures area and microcrystalline structure, so that during the charging and discharging processes of the lithium ion battery prepared from the positive electrode material, the short-term performance, such as the first charging and discharging capacity and long term performance, such as capacity retention ratio can be improved.