Titanium-Lithiated Oxide Cathode Preparation for Cycle Stability
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Solution Overview
Problem
Lithium-ion battery positive electrode active materials face performance degradation due to transition metal atom migration, leading to reduced lithium site accessibility and battery efficiency over cycles, necessitating a stable and efficient preparation method for lithiated metal oxides containing titanium.
Innovation Solution
A method involving the formation of a titanium coordination complex, followed by precipitation with optional metal salts in an aqueous basic medium, and subsequent calcination with a lithium source to produce lamellar or spinel oxides, allowing for the creation of active materials with improved particle morphology and chemical mixing, enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transition metal atoms are present in the positive electrode active material, then the material can provide lithium intercalation-deintercalation function, but the transition metal atoms migrate during cycling which blocks lithium sites and reduces battery performance
Solution Approach 1:
The patent applies preliminary action by introducing titanium dopants into the positive electrode active material before the battery cycling begins. This pre-doping stabilizes the crystal structure in advance, preventing transition metal atom migration that would otherwise occur during lithium intercalation-deintercalation cycles, thereby blocking lithium sites and reducing performance.
Solution Approach 2:
The patent employs parameter changes by modifying the chemical composition of the positive electrode active material through titanium doping. By changing the dopant concentration and type (titanium), the crystal structure stability is altered, which suppresses the migration of transition metal atoms during cycling while maintaining the lithium intercalation-deintercalation functionality.
2Reliability
If titanium is introduced as a dopant to stabilize the structure, then cycle stability is improved, but the preparation process becomes more complex
Solution Approach 1:
The patent applies merging by combining the titanium dopant with the main active material synthesis process. Instead of separate doping and material preparation steps, the titanium is introduced during the co-precipitation process, merging the dopant incorporation with the base material formation into a single integrated process, thereby reducing overall process complexity.
Solution Approach 2:
The patent uses parameter changes by optimizing the pH range (8-11) and temperature (40-80°C) of the co-precipitation process to achieve simultaneous formation of the active material and incorporation of titanium dopant. By adjusting these parameters, the preparation process remains simple while achieving stable cycling performance.
3Manufacturing precision
If co-precipitation method is used to prepare the oxide, then homogeneous mixing of metal elements is achieved, but the process requires precise control of precipitation conditions
Solution Approach 1:
The patent applies parameter changes by defining a broad and optimized pH range (8-11) and temperature range (40-80°C) for the co-precipitation process. Within these ranges, homogeneous mixing of metal elements is achieved without requiring extremely precise control, making the process easier to operate while maintaining high manufacturing precision.
Solution Approach 2:
The patent employs self-service by utilizing the automatic pH adjustment that occurs during co-precipitation when metal salts and base are mixed. The system self-regulates the precipitation conditions within the optimal range, reducing the need for complex external control mechanisms while achieving homogeneous mixing of titanium and other metal elements.
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 results in stable and efficient lithium-ion battery active materials with improved cycle stability and energy density, as demonstrated by enhanced capacitance retention and power performance compared to undoped materials.
Implementation Method 1
a step of forming a precipitate comprising titanium and the optional other metal element(s) by contacting a titanium coordination complex and, if necessary, at least one salt of the other metal element(s) with an aqueous, advantageously basic, medium
Implementation Method 2
a step of calcining the precipitate in the presence of a lithium source
Data Source
AI summary
A method for preparing a positive electrode active material for a lithium battery consisting of a lithiated oxide comprising titanium and optionally one or more other metal elements comprising the following successive steps: a) a step of forming a precipitate comprising titanium and the optional other metal element(s) by contacting a titanium coordination complex and, if necessary, at least one salt of the other metal element(s) with an aqueous medium; b) a step of recovering the precipitate thus formed; c) a step of calcining the precipitate in the presence of a lithium source.