Li-Ion Battery Electrolyte for Wide-Temperature Operation
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Solution Overview
Problem
Traditional lithium-ion batteries experience significant performance degradation at low temperatures due to high internal resistance and electrolyte decomposition at high temperatures, limiting their operational range and safety.
Innovation Solution
A wide operating temperature range secondary lithium-ion battery is designed with a specific non-aqueous electrolyte composition, including lithium salts, asymmetric carboxylate esters, and electrolyte additives, forming a stable solid electrolyte interphase with a higher inorganic lithium component ratio, enhancing conductivity and stability across −35° C. to 80° C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional lithium-ion batteries are used, then they can operate at standard temperatures, but they experience significant surge in internal resistance at low temperatures due to low ionic conductivity of the electrolyte
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by incorporating asymmetric carboxylate esters with specific molecular structures and ratios. This changes the physical-chemical properties of the electrolyte, enabling it to maintain low ionic resistance at low temperatures while preventing decomposition at high temperatures, thus resolving the temperature-range limitation of traditional electrolytes
Solution Approach 2:
The patent creates a composite electrolyte system combining asymmetric carboxylate esters with conventional carbonate solvents and lithium salts. This composite formulation leverages the unique molecular properties of asymmetric esters to form stable interphases while maintaining the beneficial ionic conductivity of traditional electrolyte components across a wide temperature range
2Temperature
If traditional lithium-ion batteries are used, then they can provide adequate capacity, but they encounter severe side reactions such as decomposition of lithium salts at high temperatures, resulting in diminished output voltage and current
Solution Approach 1:
The asymmetric carboxylate esters act as intermediary substances that form protective interphase layers between the electrolyte and electrode materials. These interphases serve as mediators that prevent direct contact and harmful side reactions between the electrolyte components and electrodes at high temperatures, while still allowing ionic transport
Solution Approach 2:
The patent converts the potential harm of electrolyte decomposition at high temperatures into a beneficial protective mechanism. The asymmetric carboxylate esters are designed to preferentially react and form stable, protective surface films that prevent further decomposition of lithium salts and other harmful side reactions, thus transforming the decomposition tendency into a protective effect
3Reliability
If conventional electrolyte composition is used, then it provides adequate ionic conductivity, but it lacks stability at high temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by incorporating asymmetric carboxylate esters with specific molecular structures and ratios. This modifies the thermal stability parameters of the electrolyte system, enabling it to resist decomposition and maintain stability at high temperatures while preserving ionic conductivity
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 battery achieves efficient discharge capabilities at low temperatures (≥2V at 1-3 C) and maintains stability after high-temperature storage, with improved safety and extended lifespan.
Implementation Method 1
the electrolyte solvent and the electrolyte additive are selected such that they synergistically react together to form a stable solid electrolyte interphase having a quantity of inorganic lithium components higher than a quantity of organic lithium components
Data Source
AI summary
A wide operating temperature range secondary lithium-ion battery designed is provided. The battery incorporates a cathode with lithium-based materials, including lithium manganese oxide, lithium cobalt oxide, lithium nickel manganese cobalt oxide, or lithium iron phosphate, and an anode with materials such as silicon, silicon oxide, carbon nanotubes, lithium metal, graphene, or graphite. A porous polymer separator, with porosity ranging from approximately 30% to 90%, ensures efficient ion transport. The non-aqueous electrolyte is composed of two or more lithium salts, including LiPF6, and a solvent mixture of carbonates and carboxylate esters with an asymmetric molecule structure. An electrolyte additive is introduced to synergistically react with the electrolyte solvents, forming a stable solid electrolyte interphase enriched with inorganic lithium components, surpassing organic lithium components. This battery configuration results in a lithium-ion battery with an extended operating temperature range from −35° C. to 85° C. for reliable energy storage under varying environmental conditions.