Li-Ion Conductive Cathode Coatings for Cycle Life and Energy Retention
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Solution Overview
Problem
Lithium-ion batteries face challenges with short cycle life due to chemical reactions between cathode materials and the liquid electrolyte, leading to energy density loss and degradation.
Innovation Solution
A cathode active material is developed with a coating comprising lithium-ion conducting oxides containing lanthanum (La) and titanium (Ti), such as Perovskite La2/3−xLi3xTiO3, or lanthanum and germanium (La and Ge), which improves the battery's average voltage and energy retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum oxide coating is applied to cathode particles to prevent transition metal dissolution, then reliability is improved, but energy density is reduced
Solution Approach 1:
The patent changes the material parameters of the coating by using lithium-ion conducting oxides (such as lithium lanthanum titanium oxide or lithium lanthanum germanium oxide) instead of conventional aluminum oxide. This parameter change enables the coating to provide both protective functions and lithium-ion conductivity, resolving the contradiction between reliability improvement and energy density loss.
Solution Approach 2:
The patent employs composite coating materials that combine lithium-ion conductivity with protective properties. The use of lithium lanthanum titanium oxide or lithium lanthanum germanium oxide creates a composite structure that simultaneously prevents transition metal dissolution and maintains lithium-ion transport, thereby improving both reliability and energy density compared to conventional coatings.
2Reliability
If coating is applied to cathode particles to prevent chemical reaction with electrolyte, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating material to achieve both protective function and lithium-ion conductivity. By selecting specific lithium-ion conducting oxides with appropriate stoichiometric ratios (controlling the ratio of La to Li), the coating provides enhanced performance while maintaining compatibility with existing manufacturing processes.
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 use of these coatings enhances the battery's performance by increasing average voltage and improving energy retention, while also stabilizing lithium cobalt oxides and allowing for more reversible lithium extraction and insertion.
Implementation Method 1
The coating can comprise a lithium (Li)-ion conducting oxide containing lanthanum (La) and titanium (Ti)
Implementation Method 2
A coating, such as aluminum oxide (Al2O3) or aluminum fluoride (AlF3), is typically applied to the cathode particles to prevent dissolution of the transition metals from the cathodes into the electrolyte
Data Source
AI summary
A cathode active material includes a plurality of cathode active compound particles and a coating disposed over each of the cathode active compound particles. The coating includes a lithium (Li)-ion conducting oxide containing lanthanum (La) and titanium (Ti).