Nitrogen-Doped Olivine Cathode for High-Temperature Battery Stability
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Solution Overview
Problem
Lithium batteries face challenges in achieving high energy density, small volume, and light weight, especially in high-temperature cyclic characteristics, which are crucial for small devices and electric vehicles, and existing cathode active materials do not adequately address these requirements.
Innovation Solution
A cathode active material with an olivine structure and nitrogen-doped core, where nitrogen is introduced by contacting the material with ammonia gas at elevated temperatures, forming a conductive and stable oxynitride or nitride phase, and optionally coated with conductive carbon, to enhance conductivity and high-rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen is doped into the olivine structure core by contacting with ammonia gas at elevated temperature, then conductivity and high-rate characteristics are improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies parameter changes by controlling the doping temperature (300-400°C) and time (1-600 minutes) to achieve optimal nitrogen doping levels. This resolves the contradiction by finding the right parameter window that improves conductivity while avoiding excessive process complexity
Solution Approach 2:
The patent uses ammonia gas as an intermediary to introduce nitrogen into the olivine structure. The ammonia serves as a nitrogen source that reacts with the material surface, forming nitrogen-doped regions without requiring complex direct nitrogen introduction equipment
2Stability of the object's composition
If the core includes nitrogen and oxygen with specific composition ratio, then structural stability is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The doping process allows the material to self-regulate the nitrogen incorporation through controlled reaction with ammonia gas. The nitrogen and oxygen composition naturally stabilizes within the desired range (N:O = 1:100 to 2.44:69.66) through the doping process itself, reducing the need for post-processing adjustment
3Productivity
If the material is contacted with ammonia gas at 300-400°C for extended time, then nitrogen doping efficiency increases, but energy consumption increases
Solution Approach 1:
The patent employs periodic doping cycles with controlled time intervals (1-600 minutes) to achieve sufficient nitrogen incorporation. By using multiple shorter doping cycles or optimized single cycles, the process achieves good doping efficiency while managing energy consumption through controlled heating periods
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 nitrogen-doped olivine structure cathode active material improves lithium battery conductivity and high-rate characteristics, maintaining structural stability and capacity, suitable for high-temperature applications in electric vehicles and other energy storage devices.
Implementation Method 1
a nitrogen atom doped into at least a portion of the core
Implementation Method 2
contacting a material having an olivine structure with a nitrogen precursor gas consisting of ammonia at 300-400°C
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4B
AI summary
A cathode active material includes a core including a material having an olivine structure, and a nitrogen atom doped into at least a portion of the core.