Composite Cathode Particles for Low-Impedance Solid-State Batteries
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Solution Overview
Problem
Conventional lithium-based solid-state batteries face issues with conductivity and impedance due to voids and side reactions between carbon additives and solid electrolyte materials, leading to degradation and cracking of cathode active material particles.
Innovation Solution
Incorporating an electrically conductive core within the cathode active material particles and coating solid electrolyte particles with a cathode active material to reduce direct contact with external conductive additives, thereby minimizing oxidation and improving internal impedance and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon additive is used to improve electron and lithium ion conductivity, then conductivity between active material particles and solid electrolyte material is improved, but decomposition of solid electrolyte material accelerates and impedance increases
Solution Approach 1:
The patent introduces an intermediary protective coating layer between the carbon additive and the solid electrolyte material. This coating prevents direct contact between the carbon and solid electrolyte, eliminating the harmful oxidation reactions while maintaining the conductive pathway. The intermediary layer acts as a barrier that allows electron and ion transport without enabling the harmful side reactions.
Solution Approach 2:
The patent employs composite material structures where carbon additives are combined with protective coating materials to form a composite conductive additive. This composite structure integrates the beneficial conductive properties of carbon with the protective characteristics of the coating material, achieving both conductivity and stability simultaneously.
2Reliability
If carbon additive is used to improve conductivity, then electron and lithium ion conductivity is enhanced, but cracking of cathode active material particles occurs
Solution Approach 1:
The protective coating serves as an intermediary layer that decouples the mechanical stress transmission between carbon additives and cathode active material particles. By preventing direct contact, the coating reduces stress concentration and crack propagation, thereby preserving the structural integrity of the particles while maintaining electrical conductivity.
3Reliability
If high surface area carbon additive is used to improve conductivity, then conductivity is enhanced, but polarization and impedance resistance increase
Solution Approach 1:
The protective coating eliminates the polarization and impedance resistance caused by direct carbon-solid electrolyte contact. By preventing the harmful electrochemical reactions at the interface, the intermediary layer reduces charge transfer resistance and polarization effects, thereby improving overall cell performance.
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 approach enhances the internal impedance and capacity retention of the cathode, reducing degradation and cracking, thus improving the overall performance of the battery.
Implementation Method 1
providing an electrically conductive core formed of an electrically conductive material, such as a carbon material, within the cathode active material particles
Implementation Method 2
decreasing the oxidation of the solid electrolyte material
Data Source
AI summary
A cathode is provided that includes a catholyte material and cathode active material particles. The cathode active material particles include an electrically conductive core and a cathode active material. The electrically conductive core is formed of an electrically conductive material. The cathode active material is disposed on a surface of the electrically conductive core.