Ionic Complex Electrolyte for High-Temperature Battery Durability
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Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges in maintaining high-temperature durability, particularly in applications like electric vehicles, where existing SEI formations deteriorate at temperatures above 45°C.
Innovation Solution
The development of an electrolyte for nonaqueous electrolyte batteries incorporating specific ionic complexes with predetermined chemical structures, such as those represented by general formula (3), which enhance high-temperature durability by forming stable Solid Electrolyte Interfaces (SEIs) with improved lithium ion conductivity and low electronic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional additive agents (vinylene carbonate, unsaturated cyclic sulfonic acid, carbon dioxide, lithium tetrafluorooxalatophosphate) are used to form SEI, then lithium ion conductivity is improved, but high-temperature durability deteriorates at 45°C or more
Solution Approach 1:
The patent changes the chemical parameters of the additive agent by introducing a specific ionic complex structure with formula (3), containing M (Al, B, Si, P, As, or Sb) bonded to X and Y groups with specific configurations. This structural parameter change enables the SEI to maintain stability at high temperatures while preserving lithium ion conductivity, resolving the contradiction between conventional additive performance and high-temperature durability
Solution Approach 2:
The patent creates a composite SEI structure by incorporating the ionic complex (containing M-X-Y framework with D anions) into the electrolyte system. This composite approach combines the benefits of conventional SEI-forming additives with the novel ionic complex structure, achieving both good lithium ion conductivity and exceptional high-temperature durability that neither component could achieve alone
2Productivity
If existing SEI formation methods are used, then initial battery performance is achieved, but cycle characteristics and storage characteristics deteriorate under high-temperature conditions
Solution Approach 1:
The ionic complex performs preliminary action by forming a stable SEI layer during initial charging that is specifically designed to resist high-temperature degradation. This pre-formed protective interface prevents subsequent deterioration during cycling and storage, maintaining battery performance over extended periods under harsh conditions
Solution Approach 2:
The patent employs a small amount (0.01-10 mass%) of the ionic complex as a sacrificial additive that decomposes during initial cycles to form the stable SEI layer. This disposable-like approach uses a minor component to create a long-lasting protective structure that benefits the entire battery lifecycle
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 ionic complexes significantly improves the cycle characteristics and storage characteristics of nonaqueous electrolyte batteries at high temperatures, maintaining performance and extending the battery's lifespan in harsh conditions.
Implementation Method 1
when a lithium cation is introduced into a negative electrode at the time of initial charging, the negative electrode and the lithium cation, or the negative electrode and an electrolyte solvent are reacted with each other to form a coating including lithium carbonate and lithium oxide as a main component on the surface of the negative electrode
Implementation Method 2
the negative electrode and an electrolyte solvent are reacted with each other to form a coating
Data Source
AI summary
To provide a material suitable for a nonaqueous electrolyte battery having high-temperature durability. An ionic complex of the present invention is represented by any of the following formulae (1) to (3). For example, in the formula (1), A is a metal ion, a proton, or an onium ion; M is any of groups 13 to 15 elements. R1 represents a hydrocarbon group which may have a ring, a heteroatom, or a halogen atom, the hydrocarbon group having 1 to 10 carbon atoms, or -N(R2)-. R2 at this time represents hydrogen, alkali metal, a hydrocarbon group which may have a ring, a heteroatom, or a halogen atom, the hydrocarbon group having 1 to 10 carbon atoms. R2 can also have a branched chain or a ring structure when the number of carbon atoms is 3 or more. Y is carbon or sulfur. When Y is carbon, r is 1. When Y is sulfur, r is 1 or 2. a is 1 or 2, o is 2 or 4, n is 1 or 2, p is 0 or 1, q is 1 or 2, and r is 0, 1 or 2. When p is 0, a direct bond is formed between S and Y.