LTO Anode Surface Coating for Gas Suppression
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Solution Overview
Problem
Lithium titanate oxide (LTO) anode materials in lithium-ion batteries generate significant gas, particularly hydrogen, at elevated temperatures, leading to reduced battery capacity and lifespan, necessitating high-temperature aging processes that decrease initial capacity.
Innovation Solution
A protective surface coating is applied to LTO materials using pretreatment compositions containing lithium fluoride salts or organophosphorus compounds, which form a fluorine, oxygen, and phosphorus or boron-based coating to suppress gas generation without requiring high-temperature aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTO anode materials are used in lithium-ion batteries, then long term cycling stability and high current efficiency are improved, but significant gas generation occurs particularly at elevated temperatures
Solution Approach 1:
A protective coating layer comprising fluorinated compounds is applied to the LTO anode material surface. This coating acts as an intermediary barrier between the LTO material and the electrolyte, preventing direct harmful interactions that lead to gas generation while allowing lithium ion transport. The coating contains fluorinated cyclic carbonate and fluorinated chain carbonate compounds that form a stable interface layer.
Solution Approach 2:
The protective coating is formulated as a composite material system combining multiple fluorinated compounds (cyclic carbonate and chain carbonate) with specific fluorine content ratios. This composite approach creates a synergistic effect where the combination of different fluorinated compounds provides superior gas suppression compared to single compounds, while maintaining electrochemical performance.
2Object-generated harmful factors
If high temperature aging processes are applied to reduce gas formation, then gas generation is suppressed, but initial battery capacity is reduced by about 10% or more
Solution Approach 1:
The protective fluorinated coating is applied to the LTO anode material before battery assembly and initial use. This preliminary protective action prevents gas generation from the outset during normal battery operation, eliminating the need for subsequent high-temperature aging processes that would otherwise be required to suppress gas formation. The coating is formed through contact with pretreatment compositions containing fluorinated lithium salts.
3Reliability
If high temperature aging is performed to improve long-term capacity retention, then gas formation is reduced, but the aging process itself decreases initial capacity
Solution Approach 1:
The fluorinated protective coating serves as a stable intermediary layer that maintains consistent lithium ion transport properties throughout battery cycling. This stable interface prevents the degradation and gas generation that would otherwise require high-temperature aging to stabilize, thereby preserving both initial capacity and long-term capacity retention without trade-offs.
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 coating significantly reduces gas formation, maintaining high battery capacity and lifespan while eliminating the need for high-temperature aging, thus enhancing the durability and performance of LTO-based lithium-ion batteries.
Implementation Method 1
contacting a surface of the electroactive material with a pretreatment composition to form a protective surface coating on the surface of the electroactive material. The protective surface coating includes fluorine, oxygen, and at least one element selected from the group consisting of: phosphorus, boron, and combinations thereof
Data Source
AI summary
Methods of pretreating an electroactive material comprising lithium titanate oxide (LTO) include contacting a surface of the electroactive material with a pretreatment composition. In one variation, the pretreatment composition includes a salt of lithium fluoride salt selected from the group consisting of: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and combinations thereof, and a solvent. In another variation, the pretreatment composition includes an organophosphorus compound. In this manner, a protective surface coating forms on the surface of the electroactive material. The protective surface coating comprises fluorine, oxygen, phosphorus or boron, as well as optional elements such as carbon, hydrogen, and listed metals, and combinations thereof.