Nitrile Electrolyte Additives for High-Voltage Li-Ion Stability
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Solution Overview
Problem
There is a need for improving the performance and safety of Li-ion batteries, particularly through the use of nitrile-based organic compounds as additives in electrolytes.
Innovation Solution
The use of nitrile-based organic compounds, specifically those with defined structural formulas, is introduced into the electrolyte of Li-ion batteries to enhance performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in Li-ion batteries, then the batteries can operate, but the performance and safety are insufficient at high voltage and temperature
Solution Approach 1:
The patent introduces nitrile-based organic compounds with specific molecular structures (containing -C≡N groups) to change the chemical composition parameters of the electrolyte. These compounds modify the electrolyte's electrochemical properties, enabling stable operation at high voltages (up to 4.5V) and temperatures where conventional electrolytes fail, thus resolving the contradiction between reliability and temperature stability.
Solution Approach 2:
The patent creates a composite electrolyte system by combining conventional electrolyte components (carbonates like EC, EMC, DMC, lithium salts like LiPF6) with nitrile-based organic compound additives. This composite approach leverages the benefits of both conventional electrolytes (good ionic conductivity) and nitrile compounds (high voltage stability), achieving improved safety and temperature resistance while maintaining operational performance.
2Reliability
If conventional electrolytes are used in Li-ion batteries, then the batteries can operate, but the electrochemical performance and stability at high voltage are insufficient
Solution Approach 1:
The nitrile-based compounds change the electrochemical window and stability parameters of the electrolyte. The -C≡N functional group provides exceptional stability against oxidation at high cathode potentials, allowing the battery to operate reliably at high voltages (4.3-4.5V) without electrolyte decomposition, thus improving electrochemical stability under high voltage stress.
Solution Approach 2:
The nitrile-based compounds act as sacrificial additives that form protective films on electrode surfaces during initial cycles. These films prevent further electrolyte decomposition and electrode degradation under high voltage conditions, effectively protecting the main electrolyte components and extending battery life despite the additives being consumed in the process.
3Productivity
If nitrile-based organic compounds are added to improve performance, then capacity and reversibility improve, but the complexity of electrolyte composition increases
Solution Approach 1:
Instead of completely reformulating the electrolyte, the patent uses small amounts (0.1-5 wt%) of nitrile-based compounds as additives to the conventional electrolyte. This partial action approach achieves significant improvements in capacity and reversibility while minimizing the increase in composition complexity, as the bulk electrolyte composition remains largely unchanged.
Solution Approach 2:
The nitrile-based organic compounds perform multiple functions simultaneously: they improve capacity, enhance reversibility, provide high-voltage stability, and offer temperature resistance. This multi-functionality means that adding a single component class addresses multiple performance issues, reducing the need for multiple different additives and thereby limiting the increase in overall system complexity.
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 nitrile-based organic compounds improve battery capacity, reversibility, and reduce resistance, leading to better stability and performance under high temperatures.
Implementation Method 1
The electrolyte may comprise organic molecules or polymers and generally also comprises a lithium salt such as LiPF6, LiTFSI or LiFSI. Moreover, the electrolyte may comprise linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC) or cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC) and butylene carbonate (BC).
Data Source
AI summary
Method of improving the performance and safety of a Li-ion battery. The method includes using a nitrile-based small organic compound of general formula I, V or IX outlined in the application in association with the electrolyte of the battery. An electrolyte including a nitrile-based small organic compound. A battery including the electrolyte.