Silane-Coated Lithium Titanium Oxide Anode for Moisture Resistance
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to electrolyte decomposition and gas generation, which can lead to swelling or explosion, particularly with lithium titanium oxide anodes that absorb moisture, necessitating complex moisture control and drying processes.
Innovation Solution
An anode active material comprising lithium metal oxide coated with a silane compound, specifically hexamethyldisilazane, to prevent moisture absorption and electrolyte decomposition, thereby enhancing safety and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lithium titanium oxide is used as an anode active material, then rapid charging time and structural stability are improved, but moisture absorption and gas generation occur
Solution Approach 1:
The patent applies composite materials by coating lithium titanium oxide particles with a silane-based coating layer. This creates a composite structure where the inner LTO core provides rapid charging capability while the outer silane coating prevents moisture absorption and subsequent gas generation, resolving the contradiction between performance and safety
Solution Approach 2:
The silane coating layer acts as an intermediary between the lithium titanium oxide and the external environment (moisture). It mediates the interaction by providing a protective barrier that prevents direct contact between moisture and LTO, thereby eliminating the harmful gas generation while preserving the rapid charging function
2Reliability
If lithium titanium oxide is used as an anode active material, then lifespan and safety are improved, but moisture control processes are required
Solution Approach 1:
The patent applies preliminary action by pre-coating the lithium titanium oxide particles with silane compound before electrode fabrication. This preliminary protective coating is applied once during material preparation, eliminating the need for continuous moisture control processes during subsequent manufacturing steps, thus reducing device complexity while maintaining reliability
3Ease of manufacture
If carbon-based material is used as an anode, then cost and conductivity are improved, but electrolyte decomposition and gas generation occur
Solution Approach 1:
The patent changes the electrochemical potential parameter of the anode material from 0V (carbon-based) to a higher potential (LTO at approximately 1.5V vs. Li/Li+). This parameter change eliminates electrolyte decomposition while the silane coating further enhances safety by preventing moisture-related gas generation, all while maintaining cost-effectiveness through the use of LTO
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 silane-coated anode active material significantly reduces gas generation and eliminates the need for moisture control processes, improving the safety and performance of lithium secondary batteries by forming a protective coating that prevents electrolyte decomposition.
Implementation Method 1
the anode active material is surface-coated with a silane compound... LTO readily absorbs moisture in air... the silane-coated anode active material significantly reduces gas generation and eliminates the need for moisture control processes
Implementation Method 2
forming a protective coating that prevents electrolyte decomposition
Data Source
AI summary
Disclosed is an anode active material comprising a lithium metal oxide represented by the following Formula 1, wherein the anode active material is surface-coated with a silane compound and a silicon content of the silane compound is 0.01 to 5% by weight, based on the total amount of the anode active material:LiaM′bO4-cAc (1) wherein M′ is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr; a and b are determined according to an oxidation number ofM′ within ranges of 0.1≤a≤4 and 0.2≤b≤4;c is determined according to an oxidation number within a range of 0≤c<0.2; andA is at least one monovalent or bivalent anion.Disclosed is also a secondary battery comprising the same.