Trigonal Lithium Nickel Oxide Additive for Stable Cathode Materials
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Solution Overview
Problem
Conventional lithium nickel oxide additives used in secondary batteries undergo multiple structural changes during operation, leading to impurity and gas generation due to de-intercalation of lithium ions, reducing energy density and stability.
Innovation Solution
Incorporating lithium nickel oxide with a trigonal crystal structure as an irreversible additive, which maintains this structure within the operating voltage range of 3.0 V to 4.0 V, minimizing structural changes and associated side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Li2NiO2 with orthorhombic crystal structure is used as irreversible additive, then lithium ion supplementation is achieved, but crystal structure changes cause impurity and gas generation
Solution Approach 1:
The patent changes the crystal structure parameter of the irreversible additive from orthorhombic to trigonal system. This parameter change eliminates the harmful structural transformations that occur in the orthorhombic Li2NiO2 during charging, thereby preventing impurity and gas generation while maintaining lithium ion supplementation capability.
Solution Approach 2:
Instead of accepting the harmful structural changes as inevitable in conventional irreversible additives, the patent inverts the approach by selecting a material (trigonal Li2NiO2 or Li2-aNi1-bM bO2-c) that fundamentally lacks these problematic transformations. This inversion of the material selection strategy eliminates the root cause of impurity and gas generation.
2Use of energy by moving object
If irreversible additive undergoes crystal structure changes during operation, then lithium ion de-intercalation occurs, but structural stability is lowered
Solution Approach 1:
The patent changes the crystal structure parameter from orthorhombic to trigonal system, which fundamentally alters the material's behavior during lithium ion de-intercalation. The trigonal structure maintains structural stability throughout the voltage range while still enabling necessary lithium ion release, thus resolving the contradiction between ion de-intercalation and structural stability.
3Quantity of substance
If orthorhombic Li2NiO2 is used as irreversible additive, then initial charge capacity is improved, but unpredictable by-products are generated during voltage changes
Solution Approach 1:
The patent changes the crystal structure parameter to trigonal system, which eliminates the unpredictable by-product formation associated with orthorhombic structure transformations. The trigonal Li2NiO2 or Li2-aNi1-bM bO2-c maintains stable structure during voltage changes, preventing by-product generation while preserving initial charge capacity improvement.
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
Reduces impurity and gas generation, enhancing the structural stability and efficiency of secondary batteries by maintaining a stable crystal structure throughout the operating range.
Implementation Method 1
lithium nickel oxide with a trigonal crystal structure as an irreversible additive, which maintains this structure within the operating voltage range of 3.0 V to 4.0 V, minimizing structural changes and associated side reactions
Data Source
Figure 1(a)~2
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AI summary
A secondary battery according to an embodiment of the present disclosure is a secondary battery including a cathode in which a cathode material is applied onto a cathode current collector, wherein the cathode material includes an irreversible additive and a cathode active material, and the irreversible additive includes lithium nickel oxide (LNO) having a trigonal crystal structure within an operating range from 3.0 V or more to 4.0 V or less in the secondary battery.