Lithium Battery Anode with Ketjen Black Shell for Volume Expansion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face issues with the volume expansion and pulverization of metal-based anode active materials during charging/discharging, leading to short cycle life and side reactions with the electrolyte, and existing solutions like carbon coating at high temperatures alter the material's structural and electrochemical properties.
Innovation Solution
An anode composition is developed with a shell containing Ketjen black applied to the metal-based anode active material, which controls volume expansion and prevents direct contact with the electrolyte, combined with carbon nano fibers for improved conductivity and dispersion, applied at a low temperature to maintain the material's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal-based anode active materials (Si, Sn) are used to increase charge/discharge capacity, then capacity is improved, but volume expansion and pulverization occur during charging/discharging
Solution Approach 1:
The patent embeds metal-based anode active material particles (Si or Sn) inside a carbonaceous material matrix. The carbonaceous material acts as a protective shell that contains the metal particles, preventing their pulverization during volume expansion while maintaining electrical contact. This nested structure allows the high-capacity metal materials to be used without suffering from their inherent structural instability.
Solution Approach 2:
The patent creates a composite anode material consisting of metal-based anode active material (Si or Sn) combined with carbonaceous material. This composite structure combines the high capacity advantage of metal materials with the structural stability and conductivity of carbon materials, achieving both high capacity and structural integrity during charging/discharging cycles.
2Duration of action of stationary object
If carbon coating is applied at high temperature to improve cycle life, then structural stability is improved, but structural features and electrochemical properties of the original material change
Solution Approach 1:
The patent changes the processing temperature parameter from high temperature to low temperature (specifically 700°C or lower, preferably 600°C or lower, more preferably 500°C or lower). This parameter change allows the carbon coating process to proceed without causing significant changes to the crystal structure or electrochemical properties of the metal-based anode active material, while still achieving protective effects and improved cycle life.
3Ease of manufacture
If conventional spherical conductive carbon fine particles are used, then manufacturing is simple, but dispersion of conductive material is insufficient
Solution Approach 1:
The patent changes the shape parameter of the conductive carbon material from spherical to flake-like. This shape change significantly improves the dispersion characteristics of the conductive material within the anode composition, creating a more uniform conductive network. The flake-like structure provides larger surface area and better interparticle contact, enhancing overall conductivity while maintaining ease of manufacture.
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 anode composition enhances the cycle life and conductivity of the metal-based anode active material, preventing deterioration and voltage drops, while maintaining the electrochemical characteristics of the material, resulting in improved battery performance and extended life.
Implementation Method 1
a shell which contains Ketjen black
Implementation Method 2
a shell which contains Ketjen black... that controls volume expansion
Implementation Method 3
combined with carbon nano fibers for improved conductivity and dispersion
Data Source
Figure 1(a)~2
AI summary
An anode composition for a lithium secondary battery includes an anode active material, a binder, and a conductive material. The active material includes a plurality of anode active material particles, each of which includes a core made of metal or metalloid allowing alloying or dealloying with lithium, or a compound containing the metal or metalloid; and a shell formed at an outer portion of the core and having Ketjen black. The conductive material includes carbon nano fiber. The anode composition uses a metal-based anode active material that may controls the volume expansion, and also uses conductive material with excellent dispersion so that the life characteristic of the battery may be improved.