Nonflammable Electrolyte for Metal Batteries
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Solution Overview
Problem
Conventional electrolytes used in metal batteries, such as lithium, sodium, and potassium batteries, are flammable and provide limited cycle life, posing safety concerns and performance issues.
Innovation Solution
A nonflammable electrolyte solution comprising a mixture of four or more salts with different anions and lithium, sodium, or potassium cations, combined with a solvent that includes a flame retardant compound and a cosolvent, such as triethyl phosphate and ethylene carbonate, to enhance safety and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in metal batteries, then the batteries can operate, but the electrolytes are flammable and provide limited cycle life
Solution Approach 1:
The patent uses a composite electrolyte system combining four or more different lithium salts (LiPF6, LiBF4, LiDFOB, LiBOB) in specific concentration ranges, creating a multi-component composite that simultaneously improves cycle life through synergistic effects and reduces flammability through the flame-retardant properties of certain salt components
Solution Approach 2:
The patent systematically varies the concentrations of each salt component within specific ranges (e.g., LiPF6: 10-40 mol%, LiBF4: 10-40 mol%, LiDFOB: 10-40 mol%, LiBOB: 10-40 mol%) to optimize the balance between electrochemical performance and safety, demonstrating that parameter adjustment can resolve the contradiction between performance and flammability
2Object-affected harmful factors
If the electrolyte composition is optimized for safety, then flammability is reduced, but cycle life and performance may be compromised
Solution Approach 1:
The patent merges the functions of multiple salts into a single electrolyte system where each component contributes specific properties: LiPF6 provides high ionic conductivity, LiBF4 enhances stability, LiDFOB and LiBOB provide flame retardancy. The combination achieves both safety and long cycle life simultaneously
Solution Approach 2:
Different salt components are distributed at specific concentration ranges to create local functional zones within the electrolyte, where flame-retardant salts (LiDFOB, LiBOB) are present in sufficient quantities to suppress flammability while conductive salts (LiPF6, LiBF4) maintain adequate ionic conductivity for performance
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 nonflammable electrolyte solution provides a safe and long-lasting cycle life for metal batteries, with a capacity retention of over 80% in 200-300 cycles and reduced gas byproduct generation, outperforming conventional electrolytes in stability and performance.
Implementation Method 1
a solvent comprising >50 vol % to 100 vol % of a flame retardant compound and 0 vol % to 50 vol % of a cosolvent
Implementation Method 2
a nonflammable electrolyte comprises a solution comprising at least four different salts, wherein (i) each salt comprises an anion with a different chemical composition than an anion of each of the other salts, (ii) cations of each of the salts are the same, the cations comprising lithium cations, sodium cations, or potassium cations
Data Source
AI summary
A nonflammable electrolyte comprises (a) at least four different salts; and a solvent comprising >50 vol % to 100 vol % of a flame retardant compound and optionally a cosolvent, wherein ((i) each salt comprises an anion with a different chemical composition than an anion of each of the other salts, (ii) cations of each of the salts are the same, the cations comprising lithium cations, sodium cations, or potassium cations, and (iii) a concentration of each of the salts is 5 mol % of a total molar concentration of the salts in the electrolyte; or (b) a difluoro(oxalato)borate or bis(oxalato)borate salt wherein a concentration of the salt is 40 mol % to 100 mol % of a total molar concentration of salts in the electrolyte, and a solvent comprising a flame retardant compound comprising an organic phosphate and a cosolvent comprising an organic carbonate solvent.