Battery Electrolyte Composition for High-Voltage Metal Stability
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Solution Overview
Problem
Existing electrochemical devices, such as lithium-ion batteries, face challenges in stabilizing high-valence transition metals and inhibiting electrolyte decomposition, leading to gas production and performance issues under high-temperature conditions.
Innovation Solution
An electrolyte composition is developed, including a compound of formula I with specific functional groups and additives like sulfur-oxygen double bond and P—O bond compounds, which stabilizes high-valence transition metals and enhances the electrolyte's stability, reducing decomposition and improving high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If charging voltage is increased to increase energy density, then energy density is improved, but electrolyte decomposition accelerates and gas production increases
Solution Approach 1:
The patent introduces a mediator substance (compound containing P-O bond and cyano group) that acts as an intermediary between the high-voltage electrode and the electrolyte. This mediator forms a protective interface layer that prevents direct contact and harmful reactions between the electrolyte and high-voltage electrode materials, enabling stable operation at charging voltages of 4.4V or higher while maintaining electrolyte stability
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific compounds with P-O bonds and cyano groups (such as lithium difluorophosphate, 1,2-bis((difluorophosphino)oxy)ethane). These parameter changes in electrolyte composition enable the system to withstand higher charging voltages without accelerating decomposition, thus resolving the contradiction between energy density and electrolyte stability
2Use of energy by moving object
If capacity of active materials is increased to increase energy density, then energy density is improved, but electrolyte decomposition accelerates and gas production increases
Solution Approach 1:
The compound containing P-O bond and cyano group serves as an intermediary that forms a stable protective layer between the active materials and electrolyte. This intermediary layer prevents harmful side reactions that would otherwise produce gas, allowing the use of high-capacity active materials without the penalty of increased gas production
Solution Approach 2:
The patent converts the potentially harmful interaction between high-capacity active materials and electrolyte into a beneficial protective interface. The initial reaction between the electrolyte additive and electrode surfaces forms a stable solid electrolyte interphase (SEI) layer that prevents further decomposition and gas generation, thus converting the harmful effect into a protective mechanism
3Use of energy by moving object
If high-valence transition metals are used to increase energy density, then energy density is improved, but metal leaching and corrosion increase
Solution Approach 1:
The patent introduces a mediator compound containing both P-O bond and cyano group that forms a protective interface layer between high-valence transition metal electrodes and the electrolyte. This intermediary layer acts as a barrier that prevents metal leaching and corrosion while allowing ionic transport, thus enabling the use of high-capacity high-valence materials without compromising metal stability
Solution Approach 2:
The electrolyte system employs a composite approach by combining multiple functional components: the P-O bond containing compound (for interface protection), cyano group compound (for metal stabilization), and conventional electrolyte solvents. This composite electrolyte formulation provides synergistic effects that simultaneously protect against metal leaching, maintain stability, and enable high energy density
4Reliability
If electrolyte decomposition is inhibited to reduce gas production, then reliability is improved, but high-temperature performance may be compromised
Solution Approach 1:
The patent changes the thermal stability parameters of the electrolyte system by incorporating compounds with specific molecular structures (P-O bond and cyano group). These structural parameter changes confer both decomposition resistance and thermal stability, allowing the electrolyte to maintain its protective function at elevated temperatures while still preventing gas production through suppressed decomposition
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 electrolyte significantly improves the high-temperature storage performance and cycle stability of electrochemical devices by inhibiting metal leaching and corrosion, and reducing impedance growth, thereby enhancing the overall performance and safety of lithium-ion batteries.
Implementation Method 1
the compound of formula I can stabilize a high-valence transition metal of the positive electrode
Implementation Method 2
inhibit the decomposition of the electrolyte
Implementation Method 3
reducing impedance growth
Data Source
AI summary
An electrolyte including at least a compound of formula I:A1, A2, and A3 are each independently selected from the following formulas I-A, I-B, I-C, or I-D, and the A1, A2, and A3 are not all I-A:m and k are 0 or 1, and n is integer from 1 to 6. R11, R13, R14, R15, R16, R17, R18, R19, R1a, R1b, R1c, and R1d are selected from hydrogen; substituted or unsubstituted C1-C10 alkylidene groups, C2-C10 alkenylene groups, C2-C10 alkynylidene groups, C3-C10 cumulative dienyl groups, C6-C10 aryl groups, or C3-C10 alicyclic hydrocarbon groups. R12 is selected from substituted or unsubstituted C1-C10 alkyl groups, C2-C10 alkenyl groups, C2-C10 alkynyl groups, C3-C10 cumulative dienyl groups, C6-C10 aryl groups, C3-C10 alicyclic hydrocarbon groups, or heteroatom-containing functional groups.