Ni-Rich Cathode Washing to Prevent Lithium Depletion
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Solution Overview
Problem
Lithium ion batteries, particularly those with Ni-rich electrode active materials, face issues due to undesired reactions on the electrode surface, such as electrolyte decomposition, which existing coatings and washing methods have not adequately addressed, leading to suboptimal electrochemical properties.
Innovation Solution
A process involving simultaneous treatment of Ni-rich electrode active materials with an aqueous medium of pH 5 to 14 followed by rapid solid-liquid separation to prevent lithium depletion and surface damage, resulting in electrode materials with improved electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrode active materials are washed with water to remove free LiOH or Li2CO3, then surface purity is improved, but lithium depletion occurs leading to degraded electrochemical properties
Solution Approach 1:
The patent changes the pH parameter of the aqueous medium to range from 5 to 14 (optimal pH 7-12), which optimizes the washing process to remove LiOH and Li2CO3 while preventing lithium depletion. This parameter optimization resolves the contradiction by finding the right chemical conditions that achieve surface purification without damaging the electrode material's electrochemical properties
Solution Approach 2:
The patent implements a rapid solid-liquid separation process immediately after brief water treatment (3 minutes or less). This rapid separation skips the prolonged exposure that would cause lithium depletion, achieving surface purification while preserving electrochemical properties by minimizing the time water contacts the material
2Manufacturing precision
If water treatment is extended to thoroughly remove LiOH and Li2CO3, then surface cleanliness is improved, but lithium depletion increases causing capacity loss
Solution Approach 1:
The patent applies partial action by limiting water treatment to brief periods (3 minutes or less) and using moderate volumes of aqueous medium. This partial treatment is sufficient to remove surface LiOH and Li2CO3 without causing excessive lithium depletion, resolving the contradiction between surface cleanliness and lithium content preservation
Solution Approach 2:
The patent performs preliminary action by conducting brief water treatment followed by immediate rapid solid-liquid separation. This preliminary washing removes surface contaminants before significant lithium depletion can occur, achieving surface cleanliness while preventing excessive lithium loss through timely separation
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 process yields electrode active materials with enhanced electrochemical properties, including reduced resistance and improved cycling stability, suitable for high-capacity lithium ion batteries.
Implementation Method 1
treating said Li1+xTM1-xO2 with an aqueous medium with a pH value in the range of from 5 to 14
Implementation Method 2
removing said aqueous medium from treated Li1+xTM1-xO2 by way of a solid-liquid separation
Data Source
AI summary
Process for modifying an electrode active material according to general formula Li1+xTM1-xO2, wherein TM contains a combination of Ni and at least one transition metal selected from Co and Mn, and, optionally, at least one metal selected from Al, Ba, and Mg and, optionally, one or more transition metals other than Ni, Co, and Mn, wherein at least 75 mole-% of TM is Ni, and x is in the range of from -0.05 to 0.2, said process comprising the steps of (a) treating said Li1+xTM1-xO2 with an aqueous medium with a pH value of at least 5 and up to 14, (b) removing said aqueous medium from treated Li1+xTM1-xO2 by way of a solid-liquid separation, wherein steps (a) and (b) are commenced with a maximum time difference of 3 minutes. In addition, the present invention is directed towards Ni-rich electrode active materials.