Isocyanate Coating for Lithium-Titanium Battery Gas Evolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous-electrolyte batteries employing lithium-titanium composite oxides as negative active materials experience gas evolution reactions due to transition metal dissolution and electrolyte decomposition, leading to deteriorated high-current characteristics and self-discharge.
Innovation Solution
Incorporating an organic compound with one or more isocyanato groups into the nonaqueous electrolyte, which reacts with water to inhibit transition metal dissolution and form a stabilizing amino compound coating on the negative electrode, preventing gas evolution and maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-titanium composite oxide is used as negative active material, then high lithium insertion/release potential and excellent cycle characteristics are achieved, but gas evolution occurs due to transition metal dissolution and electrolyte decomposition
Solution Approach 1:
An isocyanate-containing compound is introduced as an intermediary substance that mediates between the lithium-titanium composite oxide negative electrode and the nonaqueous electrolyte. This compound forms a protective coating film on the electrode surface, preventing direct harmful interactions while allowing beneficial lithium ion insertion/extraction, thus eliminating gas evolution while maintaining excellent cycle characteristics
Solution Approach 2:
The isocyanate-containing compound performs preliminary protective action by forming a stable coating film on the lithium-titanium composite oxide surface before harmful reactions can occur. This pre-formed protective layer prevents transition metal dissolution and electrolyte decomposition that would otherwise lead to gas evolution during battery operation and storage
2Productivity
If high current charging is implemented, then productivity is improved, but gas evolution accelerates and deteriorates high-current characteristics
Solution Approach 1:
The isocyanate-containing compound acts as an intermediary protective layer that enables high current charging by preventing harmful side reactions. The coating film stabilizes the electrode-electrolyte interface, allowing rapid lithium ion transport while preventing gas evolution that would otherwise accelerate at high currents, thus improving both productivity and maintaining reliable high-current characteristics
3Duration of action of stationary object
If long-term storage is performed, then battery durability is tested, but gas evolution occurs and deteriorates self-discharge characteristics
Solution Approach 1:
The isocyanate-containing compound performs preliminary protective action during long-term storage by maintaining a stable coating film on the negative electrode surface. This pre-formed protective layer prevents transition metal dissolution and electrolyte decomposition that occur during storage, thereby preventing gas evolution and maintaining excellent self-discharge characteristics over extended storage durations
Solution Approach 2:
The isocyanate-containing compound provides self-service protective function during long-term storage, continuously maintaining the protective coating film without external intervention. This self-sustaining protective mechanism prevents harmful reactions during storage, ensuring the battery maintains good self-discharge characteristics throughout its storage life
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 solution effectively inhibits gas evolution and enhances safety and performance of nonaqueous-electrolyte batteries by preventing transition metal dissolution and electrolyte decomposition, maintaining high-current characteristics and reducing self-discharge.
Implementation Method 1
an organic compound having one or more isocyanato groups having been added to the nonaqueous electrolyte
Data Source
AI summary
The invention provides a nonaqueous-electrolyte battery which has a positive electrode 3 including a positive active material, a negative electrode 4 including a negative active material having a lithium insertion/release potential higher than 1.0 V (vs. Li/Li+), and a nonaqueous electrolyte, wherein an organic compound having one or more isocyanato groups has been added to the nonaqueous electrolyte.