Cathode Precursor Pore Structure for High-Temperature Li-Ion Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high discharge capacity and resisting deterioration during high-temperature storage, as existing methods do not effectively address the degradation of battery performance under such conditions.
Innovation Solution
A precursor for a positive electrode active material is developed, characterized by specific pore structures and composition, which includes nickel, cobalt, and manganese, optimized to maintain lithium ion conductivity and prevent pore clogging, thereby enhancing the battery's discharge capacity and storage stability at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a lithium compound and precursor containing nickel, cobalt, and manganese are mixed and calcined to produce positive electrode active material, then the battery can achieve sufficient discharge capacity, but the battery deteriorates during high-temperature storage
Solution Approach 1:
The patent applies porous materials by controlling the pore structure of the precursor with specific parameters (α ≤ 2.3 m/ng, β ≤ 2.8 m/ng) to create an optimized pore network in the final cathode material. This porous structure prevents pore clogging during high-temperature storage while maintaining discharge capacity, directly resolving the contradiction between power and reliability at elevated temperatures
Solution Approach 2:
The patent employs parameter changes by precisely controlling pore structure parameters (α and β values calculated from nitrogen desorption isotherms), particle size distribution, and composition ratios of metal elements. These parameter optimizations enable the material to maintain both high discharge capacity and storage stability at high temperatures, transforming the trade-off into a balanced performance
2Power
If the pore structure of the precursor is optimized to maintain lithium ion conductivity, then discharge capacity improves, but pores may become clogged during storage
Solution Approach 1:
The patent utilizes porous materials with specifically engineered pore structures characterized by α ≤ 2.3 m/ng and β ≤ 2.8 m/ng. This optimized pore configuration maintains adequate lithium ion conductivity while preventing pore clogging during storage, directly addressing the contradiction between power and reliability
Solution Approach 2:
The patent applies preliminary action by pre-optimizing the pore structure of the precursor before battery assembly and operation. The controlled pore network is established in advance to prevent future clogging issues, ensuring both high lithium ion conductivity and long-term storage stability without requiring subsequent adjustments
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 optimized precursor ensures lithium secondary batteries maintain high discharge capacity and are less likely to deteriorate during high-temperature storage, with improved lithium ion conductivity and reduced risk of pore clogging, leading to enhanced battery performance.
Implementation Method 1
maintain lithium ion conductivity
Implementation Method 2
specific pore structures and composition, which includes nickel, cobalt, and manganese, optimized to maintain lithium ion conductivity and prevent pore clogging
Data Source
AI summary
A precursor of a positive electrode active material for a lithium secondary battery, in which a value α that is calculated by a formula (1) is 2.3 m/ng or less. (In the formula (1), A is a cumulative pore specific surface area (m2/g) for which pore diameters are 2.6 nm or more and 200 nm or less among pore specific surface areas that are obtained by analyzing a nitrogen desorption isotherm of the precursor measured at a liquid nitrogen temperature by a BJH method. V is a cumulative pore volume (cm3/g) for which the pore diameters are 2.6 nm or more and 200 nm or less among pore volumes that are obtained by analyzing the nitrogen desorption isotherm of the precursor measured at the liquid nitrogen temperature by the BJH method.)α=A2/(4πV)/1000 (1)