Solid Electrolyte Dendrite Inhibition via Additive Optimization
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Solution Overview
Problem
Lithium metal batteries face challenges with uncontrollable lithium dendrite growth and low coulombic efficiency, leading to safety hazards and reduced cycle life, which existing solid electrolytes have not adequately addressed.
Innovation Solution
A solid electrolyte composed of a polymer matrix, lithium salt, nitrile compound, and an additive ingredient, such as poly(2-vinyl-1,3-dioxolane) or its copolymer, is developed, inhibiting lithium dendrite growth and enhancing mechanical strength and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nonaqueous liquid electrolyte is used, then the battery can operate, but inflammability and safety hazards occur
Solution Approach 1:
The patent transitions the electrolyte from liquid phase to gel/solid phase by incorporating polymer materials. This phase transition eliminates the inflammability associated with liquid electrolytes while maintaining ionic conductivity, directly resolving the safety and inflammability contradiction
Solution Approach 2:
The patent creates a composite gel electrolyte system combining polymer matrix (such as polyacrylonitrile, carboxymethyl cellulose, or starch) with lithium salt and nitrile compound. This composite structure provides both the safety benefits of solid/gel phase and the ionic conductivity needed for battery operation
2Reliability
If solid electrolyte is used to inhibit lithium dendrite, then safety improves, but mechanical strength may decrease with excessive additive
Solution Approach 1:
The patent optimizes the concentration parameter of the additive ingredient (polymer or copolymer from Formula 1 or 2) within a specific range (20 to 100 parts by mass per 100 parts by mass of polymer matrix). This parameter optimization ensures sufficient dendrite inhibition while maintaining adequate mechanical strength, resolving the contradiction between protective function and structural integrity
Solution Approach 2:
The patent introduces localized functional regions by incorporating specific polymers or copolymers (such as poly(2-vinyl-1,3-dioxolane) or its copolymers) into the electrolyte matrix. These localized regions provide dendrite inhibition functionality without compromising the overall mechanical structure of the electrolyte
3Reliability
If gel/solid polymer electrolyte utilizing cationic polymerization of DOL is used, then lithium dendrite formation is inhibited, but cycle performance needs improvement
Solution Approach 1:
The patent creates a multi-component composite electrolyte system combining polymer matrix, lithium salt, nitrile compound, and specific additive ingredients. This composite structure synergistically improves both dendrite inhibition and cycle life, overcoming the limitations of simpler DOL-based gel electrolytes
Solution Approach 2:
The patent specifies precise compositional parameters including the type of lithium salt (such as LiPF6, LiBF4, LiClO4), the nitrile compound (such as acetonitrile, propionitrile), and the additive ingredient (specific polymers or copolymers with defined molecular weights). These parameter specifications optimize the electrolyte for long-term cyclic stability while maintaining dendrite suppression
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 solid electrolyte effectively inhibits lithium dendrite growth and improves cycle characteristics, achieving superior cycle performance and safety in lithium secondary batteries.
Implementation Method 1
The solid electrolyte contains a polymer matrix, a lithium salt, a nitrile compound, and an additive ingredient
Implementation Method 2
lithium metal which repeats precipitation and detachment
Implementation Method 3
dissolving the polymer matrix, the lithium salt, the nitrile compound, and the additive ingredient in a solvent
Implementation Method 4
removing most of the solvent in an atmosphere of an inert gas to form an electrolyte membrane
Implementation Method 5
vacuum-drying the electrolyte membrane at 25 to 100° C. for 2 to 48 hours
Data Source
AI summary
The present disclosure relates to a solid electrolyte for a secondary battery which inhibits growth of lithium dendrite and is superior in cycle performance, a method for manufacturing the same, and a lithium secondary battery using the solid electrolyte. The solid electrolyte includes a polymer matrix, a lithium salt, a nitrile compound, and an additive ingredient, wherein the additive ingredient is at least one selected from a polymer or a copolymer polymerized from a monomer represented by the following Formula (1), and a polymer represented by the following Formula (2):where R1 is an olefin functional group having 2 to 6 carbon atoms;where R2 is a functional group having an ionic liquid structure such as —COOCH3, imidazole, pyrrole, piperidine, and a quaternary ammonium.