Electrolyte suitable for lithium primary battery
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Solution Overview
Problem
Conventional electrolytes used in lithium-manganese dioxide batteries, such as lithium perchlorate, exhibit strong oxidizing properties, unsatisfactory high-temperature discharge performance, limited high-rate discharge performance, and safety hazards like explosibility, limiting the widespread application of these batteries.
Innovation Solution
The development of an electrolyte composition for lithium primary batteries, comprising specific lithium salts like lithium trifluoromethanesulfonate and lithium bis(trifluoromethanesulfonyl)imide, additives such as 2-trimethylsilylethyl2-cyanoacetate, diphenyldimethoxysilane, and citraconic anhydride, and a solvent blend of carbonate and glycol ether solvents, which enhances normal-temperature, high-temperature, and high-rate discharge performance while improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium perchlorate is used as electrolyte lithium salt, then ionic conductivity is achieved, but strong oxidizing property and safety hazards occur
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte lithium salt from conventional lithium perchlorate to lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, or lithium difluoro(oxalato)borate. This parameter change eliminates the strong oxidizing property while maintaining necessary ionic conductivity, directly resolving the safety hazard issue.
Solution Approach 2:
The patent employs composite electrolyte formulations by combining specific lithium salts with organic solvents and additives in defined ratios. This composite approach creates a synergistic system where the selected lithium salts work together with solvents and additives to achieve both safety and performance requirements, replacing the单一 lithium perchlorate system.
2Temperature
If conventional electrolyte composition is used, then battery structure is simple, but high-temperature discharge performance is unsatisfactory
Solution Approach 1:
The patent optimizes multiple parameters including lithium salt concentration (0.1-2.0 mol/L), additive concentrations (0.01-5.0 wt%), and solvent ratios to achieve high-temperature discharge performance. These parameter optimizations enable the electrolyte to maintain stability and conductivity at elevated temperatures without excessive complexity.
Solution Approach 2:
The patent introduces specific additives (2-trimethylsilylethyl-2-cyanoacetate, diphenyldimethoxysilane, citraconic anhydride) as intermediaries that mediate between the lithium salt and solvent system. These additives form protective films on electrode surfaces, improving high-temperature performance while maintaining reasonable system complexity through their multifunctional roles.
3Productivity
If lithium perchlorate electrolyte is used, then manufacturing is simple, but high-rate discharge performance is limited
Solution Approach 1:
The patent adjusts the concentration of lithium salts (0.1-2.0 mol/L) and optimizes the ratio of carbonate to glycol ether solvents to enhance ionic conductivity and lithium ion transport kinetics. These parameter changes directly improve high-rate discharge performance by facilitating faster ion movement through the electrolyte during high-current operation.
Solution Approach 2:
The patent employs additives such as 2-trimethylsilylethyl-2-cyanoacetate and diphenyldimethoxysilane as intermediaries that facilitate lithium ion transport at the electrode-electrolyte interface. These additives form conductive interface layers that reduce resistance and improve charge transfer kinetics, thereby enhancing high-rate discharge performance.
4Reliability
If aluminum foil is used as cathode current collector, then battery structure is simple, but corrosion by electrolyte occurs
Solution Approach 1:
The patent introduces lithium difluorophosphate and lithium difluoro(oxalato)borate as intermediary substances that react with the aluminum foil current collector to form stable passivating films. These intermediary lithium salts act as film-forming agents that create protective barriers between the aluminum foil and corrosive electrolyte components, preventing corrosion while maintaining electrical conductivity.
Solution Approach 2:
The patent employs additives such as citraconic anhydride and 2-trimethylsilylethyl-2-cyanoacetate that perform preliminary protective action by forming stable interface films on the aluminum foil before significant corrosion can occur. This preliminary film formation prevents subsequent degradation and extends the service life of the current collector.
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 solution significantly improves the discharge performance of lithium primary batteries under normal and high temperatures, enhances high-rate discharge capabilities, and ensures better safety performance compared to conventional lithium perchlorate-based electrolytes.
Implementation Method 1
lithium difluorophosphate and lithium difluoro(oxalato)borate can react with a aluminum foil on a cathode current collector of a cylindrical type lithium-manganese dioxide primary battery to form a passivating film on its surface, so that other corrosive substances can be prevented from corroding the aluminum foil
Implementation Method 2
2-trimethylsilylethyl-2-cyanoacetate, diphenyldimethoxysilane and citraconic anhydride can participate in the formation process of the passivating film on a manganese dioxide cathode material, so as to increase the film quality of the passivating film
Implementation Method 3
with the optimal selection of the solvents, not only can the dissociation degree and conductivity of the lithium salt be increased
Data Source
AI summary
The present invention relates to an electrolyte suitable for lithium primary batteries. In order to solve the problems of poor safety performance, high-rate discharge performance and discharge performance of electrolytes for conventional lithium primary batteries under high temperature, the electrolyte according to the present invention includes an electrolyte lithium salt, an additive and an organic solvent, where the electrolyte lithium salt includes one or more of lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate and lithium difluoro(oxalato)borate; the additive includes one or more of 2-trimethylsilylethyl2-cyanoacetate, diphenyldimethoxysilane and citraconic anhydride; and the organic solvent includes a carbonate solvent and an glycol ether solvent. Through the selection and combination of the electrolyte lithium salt, the additive and the solvent, the electrolyte can meet the requirement of normal-temperature discharge when applied in lithium primary batteries, so that lithium primary batteries can have normal-and-high-temperature performance, high-rate discharge performance and safety performance, and therefore, lithium primary batteries can be better popularized and applied.