Lithium Titanate Structures via Element Selective Sputtering
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Solution Overview
Problem
Lithium titanate (Li4Ti5O12) negative electrodes in lithium ion batteries suffer from significant gas production, primarily hydrogen gas, during charging, which reduces cycle life and makes them less desirable for commercial use, despite previous attempts with coatings like carbon and metal oxides that only partially suppress this issue.
Innovation Solution
A method involving element selective sputtering to form a lithium titanate structure with a conformal titanium oxide layer, isolating the lithium titanate core from the electrolyte, thereby reducing direct contact and eliminating electrolyte reduction reactions, which are the primary cause of gas production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium titanate negative electrodes are used in lithium ion batteries, then high energy density and long cycle life are achieved, but significant gas production occurs during charging that reduces cycle life
Solution Approach 1:
A conformal titanium oxide layer is introduced as an intermediary between the lithium titanate core and the electrolyte. This intermediate layer prevents direct contact between the electrolyte and lithium titanate surface, thereby eliminating electrolyte reduction reactions that produce gas, while still allowing lithium ion transport to maintain electrochemical performance and cycle life.
Solution Approach 2:
A thin conformal titanium oxide shell is formed on the lithium titanate particles through element selective sputtering. This thin film structure provides effective protection against gas production while maintaining the electrochemical performance of the underlying lithium titanate core, resolving the contradiction between reliability and harmful gas generation.
2Object-generated harmful factors
If conformal titanium oxide layer is formed via element selective sputtering, then gas production is reduced or eliminated, but manufacturing complexity increases
Solution Approach 1:
The conventional mechanical or chemical coating methods are replaced with element selective sputtering, a physical vapor deposition technique. This substitution enables precise control over the conformal layer formation process, achieving uniform titanium oxide coating on lithium titanate particles with controlled thickness and composition, thereby managing manufacturing complexity while effectively reducing gas production.
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 effectively reduces or eliminates gas production in lithium ion batteries, improving the cycle life and stability of lithium titanate electrodes by creating a conformal titanium oxide layer that prevents electrolyte reduction reactions.
Implementation Method 1
subjecting a lithium titanate precursor structure to element selective sputtering to form a lithium titanate structure including a lithium titanate core and a conformal layer on the lithium titanate core
Data Source
AI summary
A method is provided in which a lithium titanate precursor structure is subjected to element selective sputtering to form a lithium titanate structure including a lithium titanate core and a conformal layer on the lithium titanate core, wherein the conformal layer includes titanium oxide. A method of preparing an electrode for a lithium ion battery, wherein the electrode includes lithium titanate structures, is also provided.