Composite Carbon Anode Material for Fast-Charging Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current secondary batteries face limitations in capacity, energy density, charge/discharge rate, and cycling stability, particularly due to the use of graphite negative electrodes which have low theoretical specific capacity and are prone to swelling under fast charging, leading to reduced service life and reliability.
Innovation Solution
A negative active material comprising composite particles with a disordered carbon structure and an ordered carbon or metal oxide structure, which increases the energy density and diffusion coefficient of active ions, thereby enhancing the cycling and rate performance and fast charging capacity of secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite materials are used as negative electrode material, then high conductivity and high stability are achieved, but low theoretical specific capacity and swelling under fast charging occur
Solution Approach 1:
The patent uses a composite structure combining hard carbon and soft carbon materials. The hard carbon provides stable framework and swelling resistance, while the soft carbon contributes high specific capacity. This composite approach resolves the contradiction by integrating the advantages of both material types into a single functional electrode material.
Solution Approach 2:
The patent creates regions with different carbon characteristics within the electrode material. The hard carbon regions provide structural stability and swelling resistance, while soft carbon regions provide high capacity. This local differentiation allows different parts of the material to fulfill different functions, resolving the capacity-stability trade-off.
2Quantity of substance
If hard carbon materials are used to increase specific capacity, then reversible specific capacity increases to 500-700 mAh/g, but potential hysteresis and large irreversible capacity occur
Solution Approach 1:
The patent modifies the physical and chemical parameters of hard carbon by controlling particle size, pore structure, and surface area. By optimizing these parameters, the material achieves high capacity while reducing hysteresis and irreversible capacity losses, thus improving overall electrochemical performance.
Solution Approach 2:
The patent creates a heterogeneous structure with hard carbon regions providing capacity and soft carbon regions providing electrochemical stability. This local quality differentiation allows the material to achieve high reversible capacity while maintaining good cycling performance and reducing irreversible effects.
3Reliability
If graphite negative electrodes are used, then high conductivity is achieved, but swelling under fast charging reduces service life
Solution Approach 1:
The composite of hard and soft carbon creates a material that resists swelling while maintaining conductivity. The hard carbon framework provides dimensional stability during fast charging, preventing the swelling that would otherwise reduce service life, while the soft carbon maintains electrical conductivity.
Solution Approach 2:
The patent creates hard carbon regions that specifically address the swelling issue while maintaining overall electrode conductivity through the interconnected carbon structure. This local structural reinforcement prevents degradation during fast charging cycles, extending service life.
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 composite particle structure maintains capacity levels while increasing compacted density, reducing internal polarization, and improving the diffusion kinetics of active ions, resulting in improved energy density, cycling stability, and fast charging performance of secondary batteries.
Implementation Method 1
the first region includes a disordered carbon structure... the region has a disorderly-arranged internal structure and lots of pore structures, resulting in low true density and compacted density thereof
Implementation Method 2
the second region including the ordered structure can further effectively reduce a free path for the active ions, improve internal diffusion kinetics of the negative active material
Implementation Method 3
the second region including the ordered structure can further effectively reduce a free path for the active ions, improve internal diffusion kinetics of the negative active material, and reduce internal polarization of the negative active material
Data Source
AI summary
A negative active material includes composite particles. The composite particle includes a first region and a second region, where the first region includes a disordered carbon structure, and the second region includes an ordered carbon structure and/or a metal oxide structure. The negative active material of this application has a high gram capacity and active ion diffusion coefficient, so that a secondary battery containing such negative active material has a high energy density and excellent cycling performance, rate performance, and fast charging capacity.