Aromatic Carboxylic Acid Ester Electrolyte for High-Current Lithium-Ion Batteries
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges in achieving high current density charge-discharge characteristics, durability during high-temperature storage, and overcharge safety due to side reactions and increased internal resistance, which affect their overall performance and safety.
Innovation Solution
A nonaqueous electrolyte solution comprising an aromatic carboxylic acid ester compound and specific additives such as cyclic carbonate compounds with fluorine, difluorophosphate salts, and borate salts, which form composite films on electrodes to enhance conductivity and suppress side reactions, improving both charge-discharge efficiency and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of the active material layer is increased by pressing or the amount of electrolyte solution is reduced to increase battery capacity, then battery capacity increases, but the active material can no longer be used uniformly causing precipitation of lithium or deterioration of active material
Solution Approach 1:
The patent introduces a specific additive compound (formula 1) with controlled concentration (0.001-10 mass%) to modify the electrochemical parameters of the electrolyte system, enabling uniform lithium ion distribution and reaction kinetics even at high active material densities, thus resolving the contradiction between capacity and uniformity
Solution Approach 2:
The additive compound acts as an intermediary substance that mediates between the active material and electrolyte, forming a stable interface layer that facilitates uniform lithium ion transport and prevents direct harmful interactions, allowing high capacity operation without deterioration
2Quantity of substance
If gaps inside the battery are reduced to increase capacity, then battery capacity increases, but internal battery pressure increases dramatically when small amounts of gas are produced by decomposition of the electrolyte solution
Solution Approach 1:
The patent converts the potentially harmful gas decomposition products into beneficial effects by introducing the additive compound that suppresses electrolyte decomposition reactions, thereby preventing gas formation and internal pressure buildup while maintaining high battery capacity
Solution Approach 2:
The additive modifies the electrochemical stability window and decomposition characteristics of the electrolyte system, changing the parameters of gas evolution reactions to suppress harmful pressure buildup while maintaining efficient charge-discharge operation
3Use of energy by moving object
If highly active positive and negative electrodes are used to achieve higher energy densities, then energy density increases, but charge-discharge capacities are reduced by side reactions between the electrodes and the electrolyte solution
Solution Approach 1:
The additive compound serves as an intermediary that forms protective interface films on the highly active electrodes, preventing direct side reactions between electrode materials and electrolyte while maintaining efficient lithium ion transport, thus preserving charge-discharge capacity at high energy density
Solution Approach 2:
The patent creates a composite interface structure consisting of the additive-derived protective layer and the electrode surface, which combines the high reactivity benefits of active electrodes with the protective properties of the additive film, enabling both high energy density and maintained capacity
4Reliability
If various additives are included in the electrolyte solution to suppress side reactions and improve durability, then durability and safety improve, but internal resistance increases reducing charge-discharge characteristics
Solution Approach 1:
The patent optimizes the concentration parameter of the additive compound within a specific range (0.001-10 mass%) to achieve the right balance between protective film formation and electrical conductivity, suppressing side reactions and improving durability while minimizing internal resistance increase
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 significantly enhances charge-discharge characteristics at high current densities, improves durability during high-temperature storage, and ensures better overcharge safety by reducing side reactions and internal resistance, leading to a more efficient and reliable battery performance.
Implementation Method 1
an aromatic carboxylic acid ester compound represented by General Formula (1) and at least one kind of compound selected from the group consisting of cyclic carbonate compounds having fluorine atom, difluorophosphate salts, borate salts, fluorosulfonate salts, compounds having SO2 group, compounds having cyano group, oxalate salts, and Si-containing compounds
Data Source
AI summary
Provided is a nonaqueous electrolyte solution battery with dramatically improved battery characteristics. A nonaqueous electrolyte solution battery prepared by using a nonaqueous electrolyte solution comprising (I) an aromatic carboxylic acid ester compound represented by General Formula (1) below; and (II) specific compounds, is improved in charge-discharge characteristics at high current densities, durability performance during high-temperature storage and overcharge characteristics. (in General Formula (1), A1 is -R1 or -OR1, with R1 being an optionally substituted hydrocarbon group with 10 or fewer carbon atoms; A2 is an optionally substituted aryl group; each of j and k is independently 0 or an integer greater than 0, and either j or k is an integer not less than 1; and when k ≥ 1, A1 is -OR1, while when k = 0, A3 is -R1; and the case of j = 1, k = 0 is not allowed).