Li-Ion Electrolyte Composition for High-Temperature Cycling and Gas Control
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Solution Overview
Problem
Lithium-ion batteries face performance deterioration at high temperatures, leading to issues such as gas evolution and poor storage performance, which affects their energy density, cycle life, and safety.
Innovation Solution
An electrolyte with specific additives, such as sulfur-containing compounds and lithium salts, is used in combination with a positive electrode active material layer that includes lithium nickel cobalt manganate and lithium manganate, enhancing the battery's high-temperature cycle and over-discharge storage performance by forming protective layers and stabilizing interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in lithium-ion batteries, then the batteries can operate at high temperatures, but the performance deteriorates causing gas evolution and poor storage performance
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate additive as an intermediary substance that mediates between the electrolyte and electrode materials. This additive forms a stable interfacial film that prevents direct harmful interactions between the electrolyte and electrodes at high temperatures, thereby suppressing gas evolution while maintaining reliable cycling performance
Solution Approach 2:
The patent modifies the electrolyte composition by incorporating fluorinated cyclic carbonate compounds with specific molecular structures and ratios. This parameter change in the electrolyte formulation alters the decomposition behavior and film-forming characteristics, enabling the system to maintain stability at high temperatures without gas evolution
2Reliability
If conventional electrolytes are used in lithium-ion batteries, then the batteries can function at high temperatures, but the storage performance deteriorates
Solution Approach 1:
The fluorinated cyclic carbonate additive performs preliminary action by forming a stable protective film on the electrode surfaces during initial cycles. This pre-formed film acts as a barrier that prevents subsequent degradation reactions during storage, maintaining composition stability and preventing capacity loss during over-discharge storage conditions
Solution Approach 2:
The patent creates a composite electrolyte system combining fluorinated cyclic carbonate additives with conventional electrolyte components. This composite formulation synergistically combines the film-forming and stabilizing properties of the fluorinated additive with the ionic conductivity of conventional electrolytes, achieving both improved storage performance and composition 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 proposed solution improves the lithium-ion battery's high-temperature cycle performance and over-discharge storage capacity, maintaining a retention capability of 1.0 g/Ah to 4.0 g/Ah, thereby enhancing the battery's stability and safety.
Implementation Method 1
the electrolyte plays a role of transferring lithium ions between the positive electrode and the negative electrode
Implementation Method 2
an X-ray photoelectron spectroscopy of the positive active material layer has a peak at 164 eV to 175 eV
Data Source
AI summary
An electrochemical apparatus including a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode includes a positive electrode current collector and a positive active material layer disposed on the positive current collector. An X-ray photoelectron spectroscopy of the positive active material layer has a peak at 164 eV to 175 eV. The electrolyte has a retention capability of 1.0 g/Ah to 4.0 g/Ah. The electrolyte improves cycle performance, over-discharge storage performance, and safety performance of the electrochemical apparatus.