Nonaqueous Electrolyte Battery Orthoester Coating
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Solution Overview
Problem
Nonaqueous electrolyte batteries using non-fluid electrolytes face challenges with ion conductivity and durability, leading to increased resistance and degradation over time, especially when using materials with high surface areas and under high temperature conditions.
Innovation Solution
Incorporating an orthoester compound and cyclic carbonate compounds in the non-fluid electrolyte to form a stable coating film on the negative electrode, enhancing ion conductivity and reducing side reactions, while maintaining low resistance and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-fluid electrolyte is used to prevent liquid leakage and enhance safety, then safety is improved, but ion conductivity is reduced due to high viscosity
Solution Approach 1:
The patent uses a composite electrolyte system combining a non-aqueous electrolyte (containing cyclic carbonate and chain carbonate) with a solid electrolyte (sulfonated polymer). This composite structure allows the system to maintain the safety advantages of non-fluid electrolytes while the liquid components provide necessary ion conductivity, resolving the contradiction between safety and ion transport efficiency.
2Productivity
If the surface area of the negative electrode is increased to enhance reaction interface, then charge/discharge characteristics are improved, but side reactions such as solvent decomposition increase
Solution Approach 1:
The patent introduces a solid electrolyte layer that is applied in advance to the negative electrode surface before the main charge/discharge cycles begin. This preliminary coating prevents solvent decomposition and side reactions during high-surface-area operation, allowing the electrode to maintain its high reactivity without suffering from harmful side effects.
Solution Approach 2:
The solid electrolyte acts as an intermediary layer between the negative electrode and the non-aqueous electrolyte. It mediates the interaction by providing a stable interface that prevents direct contact between the electrode and reactive solvent components, thereby suppressing side reactions while still allowing ion transport.
3Quantity of substance
If a coating film is formed on the negative electrode to suppress side reactions, then initial capacity is improved, but the coating film decomposes during long-term use or high temperature storage
Solution Approach 1:
The patent creates a composite protective system where the solid electrolyte (sulfonated polymer) forms a stable, durable coating on the negative electrode. This solid polymer coating is more thermally stable and chemically resistant than conventional SEI films, maintaining its protective function during long-term storage and high-temperature operation while preserving initial capacity.
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 results in improved discharge capacity retention, reduced battery thickness, and enhanced load characteristics, even after long-term cycles and high-temperature storage, by stabilizing the electrode surface and suppressing decomposition reactions.
Implementation Method 1
by covering the surface of a negative electrode with a coating film, side reactions caused on the surface of the negative electrode, such as decomposition of a solvent, can be suppressed
Implementation Method 2
it is necessary to make it easy to cause the mass transfer by diffusion by increasing an ion conductivity of the electrolyte
Implementation Method 3
a nonaqueous electrolyte containing an electrolyte salt, a nonaqueous solvent
Data Source
AI summary
A nonaqueous electrolyte battery is provided and includes a positive electrode, a negative electrode having a negative electrode active material layer containing a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and a non-fluid electrolyte. The non-fluid electrolyte contains an electrolyte salt, a nonaqueous solvent, an orthoester compound represented by the following formula (1), and at least one member selected from the group consisting of cyclic carbonate compounds represented by the following formula (2) to (5). A volume viscosity of the negative electrode active material layer is 1.50 g/cc or more and not more than 1.75 g/cc, and a specific surface area of the negative electrode active material is 0.8 m2/g or more and not more than 4.0 m2/g