Pre-activating Lithium-Rich Cathodes to Reduce Capacity Loss
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Solution Overview
Problem
Lithium-rich layered oxide (OLO) materials suffer from significant irreversible capacity loss during the first cycle of use in electrochemical cells due to inefficient lithium extraction methods, which generate gases, create defects, and lead to poor cycle life and rate performance, making it difficult to scale up the manufacturing process.
Innovation Solution
A method involving mixing the OLO material with an activating compound, such as an organo-halide or metal halide, followed by annealing to control the extraction of lithium and oxygen, forming an activated material that reduces irreversible capacity loss and allows for the formation of stable battery electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OLO material is electrochemically activated by simultaneous extraction of lithium and oxygen during first cycle, then activation is achieved, but gas is generated leading to manufacturing problems and defects are created reducing rate capability
Solution Approach 1:
The patent applies preliminary action by performing chemical activation of OLO material before battery assembly. The material is treated with aqueous acid (e.g., HCl) to extract lithium and activate the structure in advance, so that during subsequent electrochemical cycling no additional gas is generated and no further activation defects occur. This pre-activation eliminates the harmful effects during normal battery operation.
Solution Approach 2:
The patent uses an intermediary substance (aqueous acid such as hydrochloric acid) to facilitate the activation process. The acid acts as a mediator that reacts with the OLO material to extract lithium ions and stabilize the structure without requiring simultaneous oxygen evolution. This intermediary enables activation without the harmful gas generation that occurs during direct electrochemical activation.
2Reliability
If aqueous acid is used for chemical activation to extract lithium, then activation is achieved, but water and protons are incorporated into vacancies leading to poor cycle life
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration, temperature, and duration of aqueous acid treatment to optimize lithium extraction while minimizing water incorporation. By adjusting these parameters, the activation effectiveness is maximized while the harmful incorporation of water and protons into vacancies is reduced, thereby improving cycle life.
3Productivity
If excess acid is used for chemical activation, then lithium extraction is enhanced, but control over extent of extraction is lost and wastewater disposal becomes costly
Solution Approach 1:
The patent applies feedback by monitoring and controlling the amount of lithium extracted during acid treatment, likely through measurement of pH changes, conductivity, or other indicators. This feedback mechanism allows optimization of acid quantity and treatment time to achieve the desired extraction level without using excessive acid, thereby maintaining process control and reducing wastewater treatment costs.
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 method significantly reduces irreversible capacity loss, improves rate performance, and enables the use of OLO materials in both primary and secondary batteries by pre-activating the cathode materials, maintaining particle morphology and enhancing cycle life and efficiency.
Implementation Method 1
mixing the active material and an activating compound to form a mixture. The mixture is annealed such that an amount of ions is extracted from the active material, an amount of oxygen is liberated from the active material, and an activated active material is formed.
Data Source
AI summary
A method for extracting ions from an active material for use in a battery electrode includes mixing the active material and an activating compound to form a mixture. The mixture is annealed such that an amount of ions is extracted from the active material, an amount of oxygen is liberated from the active material, and an activated active material is formed. Embodiments of the invention include the activated active material, the electrode, and the primary and secondary batteries formed from such activated active materials.