Natural Graphite Anode Material for Fast Charging and Low Swelling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Natural graphite-based negative electrode active materials for secondary batteries suffer from poor cycle swelling and rapid charging performance due to uneven particle size distribution and surface functional groups, leading to mechanical weakness and reduced cycle life.
Innovation Solution
The surface modification of natural graphite particles using potassium hydroxide (KOH) to create uniform pore distribution and increase pore size, combined with a carbon-based coating to enhance lithium ion insertion/desorption rates, improves the electrode's output and cycle swelling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural graphite particles are used as negative electrode active material, then high capacity and cost-effectiveness are achieved, but cycle swelling and rapid charging performance deteriorate due to uneven particle size distribution and surface functional groups
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution of natural graphite within a specific range (D50: 5-15 μm, Dmax/Dmin: 1.6-2.1) and modifying surface properties through KOH treatment. These parameter optimizations resolve the contradiction by maintaining high capacity while improving cycle swelling performance through uniform particle size and reduced surface functional groups.
Solution Approach 2:
The patent applies local quality by selectively treating the surface of natural graphite particles with KOH to remove surface functional groups and create a uniform pore structure. This localized surface modification improves rapid charging performance and cycle stability without affecting the bulk capacity properties of the graphite particles.
2Ease of manufacture
If natural graphite particles with wide particle size distribution are used, then manufacturing simplicity is maintained, but mechanical strength and electrode integrity deteriorate
Solution Approach 1:
The patent optimizes the particle size distribution parameters by controlling D50 between 5-15 μm and Dmax/Dmin ratio between 1.6-2.1. This parameter control maintains manufacturing simplicity while significantly improving mechanical strength and electrode integrity through uniform particle packing and reduced stress concentration.
3Power
If surface functional groups are present on natural graphite, then lithium ion insertion sites are provided, but rapid charging performance and output deteriorate due to uneven distribution and side reactions
Solution Approach 1:
The patent applies parameter changes by treating the graphite surface with KOH to reduce and uniformize the distribution of surface functional groups. This treatment eliminates uneven charge distribution and side reactions while maintaining adequate lithium ion insertion sites, thereby improving both rapid charging performance and output stability.
Solution Approach 2:
The patent converts the harmful effect of excessive surface functional groups into a benefit by using KOH treatment to selectively remove problematic groups while preserving necessary insertion sites. The treatment transforms the surface properties to achieve uniform lithium ion distribution and improved rapid charging performance without sacrificing capacity.
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 modified natural graphite active material exhibits improved rapid charging and cycle swelling performance, comparable to artificial graphite, with enhanced mechanical strength and stability, extending the battery's cycle life and energy density.
Implementation Method 1
the surface of the active material is modified through chemical activation by using KOH on the surface
Implementation Method 2
the surface of the active material is modified through chemical activation by using KOH on the surface
Implementation Method 3
a carbon-based compound capable of reversible intercalation and desorption of lithium ions
Implementation Method 4
exhibits excellent electrode life due to very reversible charge/discharge behavior
Data Source
AI summary
An anode active material for secondary batteries which has improved cycle swelling characteristics and rapid charge performance, an anode comprising same, and a method for manufacturing same, in which the anode active material is manufactured by modifying the surface of natural graphite particles. The natural graphite particles have a Dmax/Dmin value of 1.6 to 2.1 in the particle size distribution thereof and have, formed in the surface thereof, pores having a diameter of 0.5 μm to 2.0 μm.