Fluorine-Containing Solid-State Electrolyte for High Ionic Conductivity
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Solution Overview
Problem
The low ionic conductivity of fluoride electrolytes hinders the development of all-solid-state batteries suitable for high energy density applications, as they are typically limited to 10−8 S cm−1, which is insufficient for practical use.
Innovation Solution
A fluorine-containing solid-state electrolyte with a general structural formula (AX)aMBy is synthesized through a solid-phase reaction using mechanical ball milling under an inert atmosphere, forming an open frame structure with A ions in large free volume, enhancing ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fluoride solid-state electrolyte is used to achieve wide electrochemical stability window and high voltage compatibility, then oxidation stability is improved, but ionic conductivity deteriorates (typically 10^-8 S cm^-1)
Solution Approach 1:
The patent changes the chemical composition parameters by introducing dual doping elements (e.g., Ta and Al) into the fluoride electrolyte lattice, adjusting stoichiometric ratios to optimize both oxidation stability and ionic conductivity simultaneously
Solution Approach 2:
The patent creates composite fluoride electrolyte materials combining multiple elements (e.g., Li, Ta, Al, F, O) to achieve synergistic effects where the composite structure provides both high oxidation stability and enhanced ionic conductivity beyond what single-element fluorides can achieve
2Use of energy by moving object
If charge voltage is increased to enhance energy density, then energy density is improved, but electrolyte oxidation stability deteriorates
Solution Approach 1:
The patent modifies the electrolyte's electrochemical parameters through compositional adjustments, raising the oxidation potential threshold to accommodate higher charge voltages (6V or higher) required for high energy density applications
3Stability of the object's composition
If conventional electrolyte additives are used to improve resistance to high voltage, then oxidation stability is slightly improved, but energy density enhancement is limited
Solution Approach 1:
The patent fundamentally changes the electrolyte system from conventional liquid or simple solid electrolytes to doped fluoride solid-state electrolytes with tailored compositional parameters, enabling both high voltage resistance and high energy density without relying on limited additive approaches
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 fluorine-containing electrolyte achieves high ionic conductivity, enabling all-solid-state batteries with 6 V or higher voltage compatibility, suitable for high energy density cathode materials.
Implementation Method 1
performing a solid-phase reaction on AX powder and MBy powder at a stoichiometric ratio through a mechanical ball milling method under an inert atmosphere without water and oxygen
Data Source
AI summary
The present disclosure relates to the technical field of battery materials, and provides a fluorine-containing solid-state electrolyte. The fluorine-containing solid-state electrolyte has a general structural formula (AX)aMBy, where A denotes at least one of Li, Na, K, Ag, and Cu, M denotes at least one of Ti, Sn, Ta, Nb, Zr, Hf, Ga, Al, and Fe, and 0.5<a<4; B denotes F, X denotes at least one of an oxygen-containing anion and a fluorine-containing anion, and y equals 4 or 5; or B denotes at least one of F, Cl, Br, and I, X denotes BF4, and y equals 3, 4, or 5. The solid-state electrolytes according to examples of the present disclosure have the high ionic conductivities.