Composite Electrode Hard Carbon Graphite Rapid Charging
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Solution Overview
Problem
Current graphite-based electrodes in secondary batteries face limitations in rapid charging and discharging due to peeling by electrolyte solutions and low ratio characteristics, leading to reduced lifespan and capacity.
Innovation Solution
Incorporating hard carbon particles with sizes between 4 µm and 12 µm, weighing between 20% and 35% of the total weight, into the electrode structure, along with graphite particles, to enhance charging speed and lifespan by optimizing the weight percentage and loading level, and potentially adding a transition metal for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If graphite is used as electrode material to achieve appropriate energy density and ease of manufacture, then manufacturing cost and energy density are optimized, but charging speed is limited and lifespan is reduced due to peeling by electrolyte solution
Solution Approach 1:
The patent uses a composite electrode structure combining graphite particles (70-80 wt%) with hard carbon particles (20-30 wt%). The hard carbon component provides structural stability and resistance to electrolyte peeling, while graphite maintains good electrochemical performance. This composite approach resolves the contradiction by integrating the advantages of both materials to achieve both ease of manufacture and extended lifespan.
Solution Approach 2:
The patent optimizes the particle size distribution of graphite particles (0.5-5 μm) and hard carbon particles (3-15 μm), as well as their weight ratio (20-30% hard carbon). By adjusting these parameters, the electrode achieves improved structural stability and resistance to peeling while maintaining manufacturability, thus resolving the contradiction between ease of manufacture and lifespan.
2Quantity of substance
If graphite electrode is used to achieve appropriate energy density, then energy storage capacity is optimized, but charging speed is reduced due to low ratio characteristics
Solution Approach 1:
The patent creates a composite electrode with graphite particles providing high energy density (372 mAh/g) and hard carbon particles enhancing charging kinetics. The hard carbon component's superior conductivity and structural properties enable faster lithium ion insertion/extraction, resolving the contradiction between maintaining high energy density and achieving rapid charging speed.
Solution Approach 2:
The patent creates a heterogeneous electrode structure where hard carbon particles are distributed among graphite particles, creating local regions with different properties. The hard carbon regions provide fast charging pathways while graphite regions maintain high energy density, allowing the electrode to exhibit both high capacity and rapid charging characteristics simultaneously.
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 integration of hard carbon particles improves charging speed and maintains battery lifespan by increasing the maximum charge rate and reducing charging time while maintaining battery capacity and extending the number of charge discharge cycles.
Implementation Method 1
graphite particles arranged on a current collector so as to have a plurality of pores, and hard carbon particles arranged in the pores between the graphite particles
Data Source
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AI summary
An electrode is provided. The electrode includes a plurality of graphite particles arranged on a current collector so as to have a plurality of pores, and a plurality of hard carbon particles mixed with the graphite particles and having weight percent determined based on charging speed and lifespan of a battery including the electrode, wherein the weight percent of the hard carbon particles is between 20% and 35%, thereby controlling charging speed and lifespan of a battery.