Solid Electrolyte Composition for All-Solid State Battery Safety
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Solution Overview
Problem
All-solid state secondary batteries using polymer electrolytes face challenges with lithium precipitation leading to short-circuits and poor durability due to low ion conductivity and mechanical strength, despite efforts to enhance ion transportation characteristics.
Innovation Solution
A solid electrolyte composition comprising a polymer with a mass average molecular weight of 5,000 or more, an electrolyte salt with a metal ion from Group I or II, and compounds with specific polymerization reactive groups, which undergo a polymerization reaction to form a layer with high ion conductivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer electrolyte is used to improve safety, then lithium precipitates in a tree shape (dendrite) causing short-circuits and voltage abnormalities
Solution Approach 1:
By changing the polymer molecular weight to 5,000 or more, the invention creates a more uniform and stable electrolyte matrix that prevents lithium dendrite formation. The higher molecular weight polymer provides better mechanical integrity and more consistent ion transportation pathways, eliminating the voids and irregularities that cause dendritic precipitation and associated safety hazards
Solution Approach 2:
The invention creates a composite electrolyte system combining a high molecular weight polymer matrix with dissolved electrolyte salts. This composite structure provides both the mechanical strength needed to prevent dendrite penetration and the ion conductivity required for safe operation, resolving the safety contradiction
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 solution imparts high ion conductivity and excellent durability to all-solid state secondary batteries, preventing voltage abnormalities and short-circuits during charging and discharging, while maintaining mechanical strength.
Implementation Method 1
a first polymer compound having a crosslinking structure in which a (meth)acrylate compound is crosslinked by the chain polymerization (radical polymerization) of a carbon-carbon double bond
Implementation Method 2
a polymer capable of dissolving the electrolyte salt and imparting ion conductivity to the polymer electrolyte
Implementation Method 3
lithium is precipitated in a tree shape (dendrite) due to the reduction reaction of a lithium ion
Data Source
AI summary
Provided are a solid electrolyte composition containing a polymer (A) having a mass average molecular weight of 5,000 or more, an electrolyte salt (B) having an ion of a metal belonging to Group I or II of the periodic table, a compound (C) having three or more polymerization reactive groups, and a compound (D) having two or more polymerization reactive groups that are polymerization reactive groups different from the polymerization reactive groups that the compound (C) has and are capable of causing a polymerization reaction with the polymerization reactive groups that the compound (C) has, a solid electrolyte-containing sheet and an all-solid state secondary battery that are obtained using the solid electrolyte composition, and methods for manufacturing a solid electrolyte-containing sheet and an all-solid state secondary battery.