Lithium Complex Electrolyte for Low-Resistance Battery Cycling
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Solution Overview
Problem
Current non-aqueous electrolytes for lithium secondary batteries face challenges in achieving low electrical resistance and maintaining high cycle properties, particularly when used in solid-state batteries, due to limitations in solubility and lithium ion conductivity.
Innovation Solution
A novel lithium-containing complex compound is introduced, represented by specific formulas, which is soluble in non-aqueous solvents, providing low electrical resistance and excellent lithium ion conductivity, enabling the use of a solid-state lithium secondary battery without the risk of firing associated with organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium salts (LiBF4, LiPF6) are used in non-aqueous electrolytes, then high voltage and high energy density are achieved, but electrical resistance remains high and cycle properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing lithium-containing complex compounds with specific structures (formulas 1-5) that have different coordination environments and bonding characteristics compared to conventional lithium salts. This structural parameter change enables simultaneous improvement in electrical resistance and cycle properties
Solution Approach 2:
The patent uses composite electrolyte systems combining lithium-containing complex compounds with conventional lithium salts and carbonate solvents. The composite structure allows the novel compound to form protective interfaces while the conventional components maintain bulk conductivity, resolving the contradiction between resistance and cycle stability
2Object-affected harmful factors
If solid-state lithium compounds are used to eliminate organic solvent flammability, then safety is improved, but solubility in non-aqueous electrolytes becomes insufficient
Solution Approach 1:
The patent applies local quality by designing lithium-containing complex compounds that exhibit different solubility characteristics in different regions of the electrolyte system. The compounds have high solubility in carbonate solvents at the electrode interface while maintaining low volatility and flammability in the bulk phase, thus achieving both safety and solubility requirements
Solution Approach 2:
The lithium-containing complex compounds act as intermediaries between solid-state safety requirements and liquid electrolyte solubility needs. These compounds can dissolve in carbonate solvents to form conductive species while their molecular structure inherently provides flame retardancy, mediating the contradiction between safety and solubility
3Use of energy by moving object
If non-aqueous electrolytic solutions are used to achieve high energy density, then voltage and capacity are improved, but the risk of firing due to organic solvent flammability increases
Solution Approach 1:
The patent converts the harmful flammability of organic solvents into a benefit by using lithium-containing complex compounds that contain fluorine atoms and specific bonding structures. These structures inherently suppress flame propagation while maintaining the electrochemical performance needed for high energy density, thus converting the safety hazard into a safety feature
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 novel electrolyte achieves improved initial and cycle properties for lithium secondary batteries, including low resistance and enhanced lithium ion conductivity, making it suitable for both non-aqueous and solid-state battery applications.
Implementation Method 1
a non-aqueous electrolytic solution with low electrical resistance can be obtained, a lithium secondary battery excellent in favorable initial properties and cycle properties is obtained and further, since the electrolyte itself has excellent lithium ion conductivity
Implementation Method 2
a non-aqueous electrolytic solution which has a role to transfer lithium ions
Data Source
AI summary
To provide an electrolyte for a storage device capable of lowering the electric resistance and maintaining a high capacity even after charging and discharging are repeatedly carried out, and a storage device.An electrolyte for a storage device, which comprises a lithium-containing complex compound represented by the following formula (1), (2), (3), (4) or (5):(Li)m(A)n(UFx)y (1)(Li)m(Si)n(O)q(UFx)y (2)wherein A is O, S, P or N; U is a boron atom or a phosphorus atom; m and n are each independently from 1 to 6; q is from 1 to 12; x is 3 or 5; and y is from 1 to 6;(Li)m(O)n(B)p(OWFq)x (3)wherein W is a boron atom or a phosphorus atom; m, p and x are each independently from 1 to 15; n is from 0 to 15; and q is 3 or 5;(Li)m(B)p(O)n(OR)y(OWFq)x (4)wherein W is a boron atom or a phosphorus atom; n is from 0 to 15; p, m, x and y are each independently from 1 to 12; q is 3 or 5; and R is hydrogen, an alkyl group, an alkenyl group, an aryl group, a carbonyl group, a sulfonyl group or a silyl group, and such a group may have a fluorine atom, an oxygen atom or other substituent;(Li)m(O)n(B)p(OOC-(A)z-COO)y(OWFq)x (5)wherein W is a boron atom or a phosphorus atom, A is a C1-6 allylene group, alkenylene group or alkynylene group, a phenylene group, or an alkylene group having an oxygen atom or a sulfur atom in its main chain; m, p, x and y are each independently from 1 to 20; n is from 0 to 15; z is 0 or 1; and q is 3 or 5.