Electrolyte Additive Complexation for High-Temperature Li-Ion Cycling
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving higher energy density, safety, and stability, particularly at high temperatures, which affects their storage and cycle performance.
Innovation Solution
The development of an electrolyte containing a phosphine oxide polycyano functional group compound, which forms a complex with transition metals in the positive electrode active material, enhancing oxidation resistance and inhibiting electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in lithium-ion batteries, then basic electrochemical performance is maintained, but high-temperature storage performance and cycle performance deteriorate due to electrolyte decomposition and gas production
Solution Approach 1:
The phosphine oxide polycyano functional group compound acts as an intermediary substance that forms a complex with transition metals on the positive electrode surface. This complex serves as a mediator that provides oxidation resistance and prevents electrolyte decomposition, thereby improving high-temperature storage performance and cycle performance without compromising basic electrochemical function
Solution Approach 2:
The invention employs a composite electrolyte system comprising multiple components: cyclic carbonate solvents (EC, PC), chain carbonate solvents (DMC, DEC, EMC), lithium salt (LiPF6), and the phosphine oxide polycyano functional group compound. This composite electrolyte formulation works synergistically to provide both standard electrochemical performance and enhanced high-temperature stability
2Duration of action of stationary object
If conventional electrolytes are used, then basic battery operation is maintained, but cycle performance deteriorates due to continuous electrolyte decomposition at high temperatures
Solution Approach 1:
The phosphine oxide polycyano functional group compound performs preliminary anti-action by forming a protective complex with transition metals on the positive electrode surface before significant electrolyte decomposition can occur. This pre-formed complex provides oxidation resistance that prevents continuous electrolyte decomposition during cycling, thereby extending battery cycle life
Solution Approach 2:
The phosphine oxide compound serves as an intermediary that mediates between the positive electrode and the electrolyte. By forming a stable complex with transition metals, it creates a protective interface that reduces direct contact between the electrolyte and reactive electrode surfaces, thereby reducing decomposition rate and improving cycle performance
3Reliability
If conventional electrolytes are used, then normal battery function is maintained, but gas production increases at high temperatures reducing storage performance
Solution Approach 1:
The phosphine oxide polycyano functional group compound acts as an intermediary that forms a complex with transition metals on the positive electrode. This complex reduces the catalytic activity of transition metals toward electrolyte decomposition reactions that produce gas, thereby suppressing gas generation during high-temperature storage and improving storage performance
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 proposed electrolyte significantly improves the high-temperature storage performance, cycle performance, and floating charge performance of lithium-ion batteries by stabilizing the positive electrode and reducing gas production.
Implementation Method 1
forms a complex with transition metals in the positive electrode active material
Implementation Method 2
enhancing oxidation resistance and inhibiting electrolyte decomposition
Implementation Method 3
enhancing oxidation resistance and inhibiting electrolyte decomposition
Data Source
AI summary
An electrolyte includes a compound represented by formula I-A, where A1, A2, and A3 are each independently selected from formula I-B or formula I-C, and at least two of A1, A2, and A3 are formula I-C. In formula I-A, n is selected from integers 1 to 10, and m is selected from 0 or 1. In formula I-B and formula I-C, represents a site at which two adjacent atoms are joined. The electrolyte can significantly improve high-temperature storage performance, cycle performance, and floating charge performance of the electrochemical device.