Nano-crystalline Graphene Electrodes for Li-Ion Batteries
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Solution Overview
Problem
Lithium ion batteries with traditional electrodes have low power and energy density due to slow lithium diffusion and low electrical conductivity, and the inclusion of binders and conductors further reduces energy density.
Innovation Solution
The use of nano-crystalline graphene as electrodes in lithium ion batteries, which includes a plurality of graphene layers with specific grain sizes and structures, eliminates the need for binders and conductors, enhancing conductivity and adsorbability, and incorporates oxygen double bonds for efficient lithium ion interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional electrodes with binders and conductors are used, then structural stability is maintained, but energy density and power density are reduced
Solution Approach 1:
The patent extracts and removes the binder and conductor components from the electrode structure, using only pure lithium transition metal oxide particles. This eliminates unnecessary materials that do not contribute to energy storage, thereby increasing energy density while simplifying the electrode structure.
Solution Approach 2:
The patent applies a conductive coating layer selectively on the surface of lithium transition metal oxide particles. This local quality approach provides conductivity where needed (at the particle surface for electron transport) while maintaining the pure oxide structure in the bulk for high energy density.
2Power
If traditional electrodes with binders and conductors are used, then structural stability is maintained, but power density is reduced
Solution Approach 1:
The patent changes the particle size parameter of lithium transition metal oxide to the nanometer range (1-100 nm). This parameter change dramatically increases the surface area to volume ratio, providing more pathways for lithium ion diffusion and significantly improving both power density and diffusion speed.
Solution Approach 2:
The patent creates a composite structure where lithium transition metal oxide particles are coated with a conductive material layer. This composite structure enhances electrical conductivity at the particle level, improving electron transport speed and overall power density without requiring bulk binders or conductors.
3Quantity of substance
If conductors and binders are included in anode material, then structural integrity is maintained, but energy density is reduced
Solution Approach 1:
The patent removes binders and conductors from the anode material composition, using only lithium transition metal oxide particles. This extraction eliminates non-active materials that reduce energy density while the nanoscale particle structure and conductive coating maintain necessary structural integrity for battery operation.
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
This configuration increases the power and energy density of lithium ion batteries by improving lithium ion insertion and discharge velocities and reducing electrical resistance, while maintaining high conductivity and adsorption capabilities.
Implementation Method 1
the cathode may include oxygen double bonds with carbons of the nano-crystalline graphene, and the oxygen double bonds may combine with lithium ions in a discharging process and are separated from the lithium ions in a charging process
Implementation Method 2
A lithium ion battery uses lithium as a carrier ion
Implementation Method 3
nano-crystalline graphene having conductivity and/or adhesiveness is directly used as electrodes
Data Source
AI summary
Provided are lithium ion batteries including a nano-crystalline graphene electrode. The lithium ion battery includes a cathode on a cathode current collector, an electrolyte layer on the cathode, an anode on the electrolyte layer, and an anode current collector on the anode. The anode and the cathode include a plurality of grains having a size in a range from about 5 nm to about 100 nm. The cathode has a double bonded structure in which a carbon of the graphene is combined with oxygen.