Metal Nitride-Coated Anode Material for Fast-Charging Li-Ion Batteries
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high initial efficiency, long cycle-life characteristics, and fast chargeability, particularly due to issues with lithium ion intercalation and the formation of lithium metal dendrites.
Innovation Solution
A negative active material is developed comprising a carbonaceous core with a metal-including nitride on its surface, which has lower lithium adsorption and diffusion energies, prepared through a process involving coating crystalline carbon with a metal compound, primary and secondary heat-treatment, and a magnesium powder etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbonaceous materials are used as negative active material, then the battery structure is simple and manufacturing is easy, but the initial efficiency is low and cycle-life is short
Solution Approach 1:
The patent applies composite materials by combining carbonaceous core particles with a metal-including nitride coating layer. The core includes carbonaceous material (graphite, amorphous carbon, etc.) and the coating layer comprises metal nitride (TiN, ZrN, HfN, etc.), forming a composite structure that leverages the advantages of both materials: the carbonaceous core provides stable lithium ion intercalation while the metal nitride coating reduces interface resistance and prevents dendrite formation, thereby extending cycle-life without excessive complexity
Solution Approach 2:
The patent applies local quality by creating a coated structure where the metal-including nitride layer is applied only on the surface of the carbonaceous core particles. This localized modification allows the bulk carbonaceous material to maintain its intercalation properties while the surface coating provides protective functions (reducing interface resistance, preventing dendrites), achieving improved reliability without uniformly complicating the entire material structure
2Productivity
If conventional carbonaceous materials are used, then manufacturing process is simple, but fast chargeability is poor due to high lithium ion diffusion energy
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of carbonaceous materials through coating with metal-including nitride. This changes the interface characteristics (reducing interface resistance) and lithium ion diffusion energy at the surface, enabling faster lithium ion transport and improving fast chargeability while the core manufacturing process remains relatively simple
Solution Approach 2:
The metal-including nitride coating acts as an intermediary layer between the carbonaceous core and the electrolyte. This intermediate layer facilitates lithium ion transfer by reducing interface resistance and providing a low-diffusion-energy pathway, thereby improving fast chargeability without fundamentally changing the core manufacturing process
3Reliability
If conventional carbonaceous materials are used, then the material structure is simple, but lithium metal dendrites form reducing safety and cycle-life
Solution Approach 1:
The patent applies preliminary anti-action by pre-coating the carbonaceous core with metal-including nitride before battery assembly. This preliminary protective layer prevents the formation of lithium metal dendrites by reducing interface resistance and providing a stable surface, thereby improving safety and cycle-life before any harmful effects can occur
Solution Approach 2:
The patent converts the potentially harmful interaction between carbonaceous materials and lithium ions (which can lead to dendrite formation) into a beneficial process by introducing the metal-including nitride coating. This coating transforms the high-diffusion-energy, dendrite-prone interface into a low-diffusion-energy, dendrite-resistant interface, turning a harmful characteristic into a beneficial one
4Use of energy by moving object
If conventional carbonaceous materials are used, then interface resistance is high, but the material structure and manufacturing process remain simple
Solution Approach 1:
The patent applies parameter changes by modifying the interface properties through metal-including nitride coating. This changes the electrical and chemical characteristics of the carbonaceous material surface, reducing interface resistance and improving lithium ion transfer efficiency, while adding only a thin coating layer that doesn't significantly complicate the overall material structure
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 material enhances lithium ion intercalation, reduces interface resistance, and prevents the formation of lithium metal dendrites, resulting in improved fast chargeability and cycle-life characteristics.
Implementation Method 1
a metal-including nitride on a surface of the core and having lower lithium adsorption energy and lower lithium ion diffusion energy than the core
Implementation Method 2
primary heat-treating the primary coating material to prepare a primary heat-treated product; secondary heat-treating the mixture under a nitrogen atmosphere to prepare a secondary heat-treated product
Data Source
AI summary
Disclosed are a negative active material, a method of preparing the same, and a rechargeable lithium battery including the same. The negative active material includes a core including a carbonaceous material; and a metal-including nitride on a surface of the core and having lower lithium adsorption energy and lower lithium ion diffusion energy than the core.