Composite Cathode Material With Polymer-Bonded Solid Electrolyte
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Solution Overview
Problem
Conventional methods for preparing composite positive electrode active materials for lithium secondary batteries using high-nickel content materials face challenges such as low moisture stability, difficulty in adhering inorganic solid electrolytes due to high-temperature firing, and potential deterioration of electrochemical properties, leading to aggregation and detachment of particles.
Innovation Solution
A composite positive electrode active material is developed with oxide-based solid electrolyte particles adhered to the surface of positive electrode active material particles via a crosslinked polymer binder, allowing for a simplified process at relatively low cure temperatures, thereby stabilizing the adherence and improving capacity, output, and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature firing is used to adhere solid electrolyte particles, then adhesion strength is improved, but crystal structure changes and electrochemical properties deteriorate
Solution Approach 1:
The patent uses a polymer binder as an intermediary substance to adhere solid electrolyte particles to the positive electrode active material particles. This binder acts as a mediator that provides adhesion strength without requiring high-temperature firing, thereby preventing crystal structure changes and maintaining electrochemical properties while still achieving effective particle bonding.
2Strength
If high-temperature firing is used to adhere solid electrolyte particles, then adhesion is improved, but particle aggregation occurs
Solution Approach 1:
The polymer binder serves as an intermediary that enables particle adhesion at low temperatures, preventing the thermal energy from causing particle aggregation while still achieving sufficient bonding strength to hold solid electrolyte particles on the active material surface.
Solution Approach 2:
The patent changes the temperature parameter from high-temperature firing to low-temperature curing, which fundamentally alters the adhesion mechanism from thermal bonding to polymer-based bonding, thereby preventing particle aggregation while maintaining adhesion effectiveness.
3Reliability
If low-temperature firing is used to avoid crystal structure changes, then electrochemical properties are maintained, but solid electrolyte particles detach
Solution Approach 1:
The polymer binder acts as an intermediary substance that provides the necessary adhesion strength at low temperatures, compensating for the lack of thermal bonding while maintaining electrochemical properties by preventing particle detachment through chemical and physical bonding mechanisms.
4Manufacturing precision
If wet mixing method is used to prepare composite material, then mixing uniformity is improved, but moisture stability deteriorates
Solution Approach 1:
The patent extracts the liquid solvent from the mixing process by using a dry mixing method, thereby eliminating the moisture introduction that causes stability deterioration while still achieving uniform mixing through mechanical dispersion of particles without liquid medium.
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 composite material enhances the capacity, output, and conductivity of lithium secondary batteries while maintaining the stability of the positive electrode active material, reducing the risk of crystal structure changes and particle aggregation, and improving safety.
Implementation Method 1
oxide-based solid electrolyte particles are adhered to the surface of the positive electrode active material particles via the crosslinked polymer binder
Implementation Method 2
a crosslinked polymer binder formed on the positive electrode active material particles
Data Source
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AI summary
The present disclosure relates to a composite positive electrode active material to which an oxide-based solid electrolyte can be adhered to improve the conductivity, capacity, and output characteristics of a lithium secondary battery, without deteriorating the physical properties of a positive electrode active material itself, a preparation method thereof and a lithium secondary battery comprising the same. The composite positive electrode active material includes: positive electrode active material particles; and oxide-based solid electrolyte particles formed on the positive electrode active material particles and a crosslinked polymer binder, wherein the oxide-based solid electrolyte particles are adhered to the surface of the positive electrode active material particles via the crosslinked polymer binder.