Nano-Structured Positive Electrode Material for Fast-Charging Batteries
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Solution Overview
Problem
Lithium ion batteries face challenges with low conductivity and limited charging and discharging rates due to the low conductivity of lithium oxide materials used as positive electrode active materials, which restricts the performance of power storage devices.
Innovation Solution
The use of nano-sized lithium oxide materials with specific grain sizes and surface areas, supported by carbon materials, to enhance the diffusion path and conductivity, thereby improving the charging and discharging rates and capacitance of power storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium oxide is used as positive electrode active material, then the material can store large electricity with compact structure, but the conductivity is low and charging/discharging rates are limited
Solution Approach 1:
The lithium oxide particles are divided into fine particles with a grain size of 10 nm to 100 nm. This segmentation increases the surface area per unit mass and shortens the diffusion path for lithium ions, thereby improving conductivity and charging/discharging rates while maintaining high electricity storage capacity.
Solution Approach 2:
The grain size parameter of the lithium oxide is changed to a specific range (10 nm to 100 nm) to optimize both conductivity and storage capacity. This parameter change transforms the material from low-conductivity bulk form to high-conductivity nano-form, resolving the contradiction between storage capacity and power output.
2Power
If grain size of active material is reduced to increase diffusion path, then charging and discharging rates improve, but manufacturing precision becomes more difficult to control
Solution Approach 1:
A specific grain size range (10 nm to 100 nm) is established as the optimal parameter window that balances manufacturing feasibility with performance requirements. This parameter specification makes the nano-sizing process controllable and reproducible in manufacturing while achieving the desired diffusion path length for high charging/discharging rates.
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 approach results in higher charging and discharging rates, increased capacitance, and reduced internal resistance, leading to improved power storage device performance.
Implementation Method 1
By utilizing the high conductivity of the carbon material, the internal resistance of a power storage device is reduced
Implementation Method 2
a diffusion path of a reactive material (e.g., lithium ions) is increased by nano-sizing a grain size of an active material
Data Source
AI summary
An object is to improve the characteristics of a power storage device such as a charging and discharging rate or a charge and discharge capacity. The grain size of particles of a positive electrode active material is nano-sized so that a surface area per unit mass of the active material is increased. Specifically, the grain size is set to greater than or equal to 10 nm and less than or equal to 100 nm, preferably greater than or equal to 20 nm and less than or equal to 60 nm. Alternatively, the surface area per unit mass is set to 10 m2/g or more, preferably 20 m2/g or more, further, the crystallinity of the active material is increased by setting an XRD half width to greater than or equal to 0.12° and less than 0.17°, preferably greater than or equal to 0.13° and less than 0.16°.