Graphite Anode Carbon Coating for Battery Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous electrolyte secondary batteries using graphite particles as negative electrode active material face durability issues due to peeling of scaly graphite during charge and discharge cycles, leading to decreased conductivity and capacity retention.
Innovation Solution
Incorporating carbon black into the internal voids and surface of graphite particles in the negative electrode active material, forming a carbon coating, maintains conductive paths and reduces surface reactivity, thereby enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If graphite particles are used as negative electrode active material, then energy density is improved, but durability decreases due to peeling of scaly graphite during charge and discharge cycles
Solution Approach 1:
The patent applies composite materials by combining graphite particles with carbon black to form a core-shell structure. The graphite core provides high energy density while the carbon black coating maintains structural integrity and conductivity during charge-discharge cycles, preventing peeling and improving durability.
Solution Approach 2:
The patent modifies the surface properties of graphite particles by controlling the carbon black coating thickness and composition. This parameter change maintains good conductive paths while reducing surface reactivity and preventing graphite peeling during electrochemical cycling.
2Reliability
If carbon coating is formed on graphite particles, then conductivity is maintained, but capacity retention decreases
Solution Approach 1:
The patent applies local quality by creating a non-uniform carbon black distribution on graphite particles. The carbon black is concentrated in internal voids and selectively distributed on the surface, providing localized conductivity enhancement where needed while preserving lithium insertion/extraction sites for capacity retention.
Solution Approach 2:
The patent utilizes the porous structure of graphite particles with internal voids that are filled with carbon black. This porous configuration maintains conductive paths within the particle interior while preserving the overall particle structure and lithium 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 carbon coating on graphite particles effectively curtails decreases in durability and capacity retention, particularly when using 1 to 10 parts by weight of carbon black relative to graphite, maintaining suitable energy density and conductivity.
Implementation Method 1
part of the carbon black accumulates on the surface of the graphite particles thereby forming a carbon coating portion
Data Source
AI summary
Provided is a technique that allows curtailing decreases in the durability of a nonaqueous electrolyte secondary battery. A negative electrode active material disclosed here is a particulate negative electrode active material used in a nonaqueous electrolyte secondary battery. The negative electrode active material contains graphite particles which are aggregates of scaly graphite, and carbon black. The carbon black is present in internal voids of the graphite particles, and part of the carbon black accumulates on the surface of the graphite particles thereby forming a carbon coating portion.