Nitrile-Based Battery Electrolyte for High-Temperature Cycle Life
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high energy density, high capacity, and improved lifespan and high-temperature storage characteristics.
Innovation Solution
Incorporating a nitrile-based additive in the electrolyte, along with specific olivine-structured positive electrode active materials, to form a stable film on the electrode surface, reducing side reactions and gas generation, and enhancing the battery's lifespan and storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional electrolytes are used to achieve high energy density and high capacity, then battery performance is improved, but lifespan and high-temperature storage characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a nitrile-based additive with specific molecular structure (Chemical Formula 5), which modifies the electrolyte's interaction with electrode surfaces to form stable protective films, thereby improving lifespan and storage characteristics while maintaining high energy density
Solution Approach 2:
The nitrile-based additive acts as an intermediary substance between the electrolyte and electrode surfaces, forming a stable interfacial film that mediates the interaction to prevent harmful side reactions and metal dissolution, thus protecting the battery system while preserving its high energy density performance
2Quantity of substance
If conventional electrolytes are used to achieve high capacity, then battery performance is improved, but side reactions and gas generation increase
Solution Approach 1:
The patent converts the potentially harmful interaction between conventional electrolytes and electrode surfaces into a beneficial protective mechanism by using the nitrile-based additive to form stable films that prevent further harmful side reactions and gas generation, while allowing high capacity operation
3Ease of operation
If conventional electrolytes are used, then battery operation is maintained, but transition metal dissolution occurs during high-temperature storage
Solution Approach 1:
The nitrile-based additive serves as a protective intermediary that forms stable films on electrode surfaces during high-temperature storage, preventing direct contact between the electrolyte and transition metals, thereby eliminating metal dissolution while maintaining normal battery operation
Solution Approach 2:
The patent creates a chemically inert protective environment at the electrode-electrolyte interface through the nitrile-based additive film, which isolates the transition metals from the electrolyte even under high-temperature conditions, preventing dissolution and maintaining compositional stability
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 additive forms a stable film, suppressing reductive decomposition and transition metal dissolution, thereby improving battery resistance and lifespan, especially during high-temperature storage.
Implementation Method 1
The nitrile-based additive forms a stable film on the electrode surface
Data Source
AI summary
An electrolyte and a rechargeable lithium battery including the electrolyte are provided. The rechargeable lithium battery includes a positive electrode that includes a positive electrode active material, a negative electrode that includes a negative electrode active material, and an electrolyte. The electrolyte includes a nitrile-based additive. The positive electrode active material includes at least one selected from among compounds represented by Lia1Fex1B1y1PO4-b1 and Lia2Mnz2Fex2B1y2PO4-b2, where B1 is at least one element selected from among Ti, Mg, V, and Nb.