Dual-Layer Electrolyte for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium secondary batteries face issues with lithium dendrite growth during charging, leading to short circuits and reduced lifespan, particularly due to the limitations of general solid electrolytes in preventing dendrite formation.
Innovation Solution
A secondary battery design incorporating a dual-layer electrolyte system with a first electrolyte layer having inorganic particles with an average diameter of less than 500 nm and a second layer with particles of 500 nm or greater, where the first layer faces the anode, enhancing ion conductivity and mechanical properties while suppressing dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a general solid electrolyte is used, then the battery structure is simple, but lithium dendrite growth occurs leading to short circuits and reduced lifespan
Solution Approach 1:
The electrolyte is divided into two distinct layers: a first electrolyte layer containing inorganic particles with D50 < 500 nm facing the anode, and a second electrolyte layer containing inorganic particles with D50 ≥ 500 nm. This segmentation allows each layer to perform specialized functions - the first layer suppresses dendrite growth while the second layer maintains ion conductivity, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
Different regions of the electrolyte are assigned different particle size characteristics tailored to local requirements. The first electrolyte layer near the anode uses fine particles (D50 < 500 nm) for optimal dendrite suppression, while the second layer uses coarser particles (D50 ≥ 500 nm) for maintaining bulk ion conductivity. This local differentiation optimizes performance without unnecessary complexity throughout the entire electrolyte.
2Reliability
If inorganic particles are added to the electrolyte, then dendrite growth is suppressed, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies quantitative parameter ranges for inorganic particle sizes (D50 < 500 nm for first layer, D50 ≥ 500 nm for second layer) and their weight ratios (1-30 parts by weight based on 100 parts polymer). These defined parameters provide clear manufacturing targets while allowing sufficient tolerance ranges, balancing dendrite suppression effectiveness with manufacturability.
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 dual-layer electrolyte structure effectively prevents lithium dendrite growth, improving the battery's lifespan and maintaining low internal resistance, as demonstrated by extended cycle test results without short circuits.
Implementation Method 1
a first electrolyte layer including a first polymer, a first lithium salt, and a first particle inorganic material having an average particle diameter (D50) of less than 500 nm
Implementation Method 2
The first electrolyte layer is in a direction facing the anode... A total thickness of the first electrolyte layer and the second electrolyte layer may be 20 μm or less
Data Source
AI summary
A secondary battery includes a cathode; an anode; and an electrolyte between the cathode and the anode, wherein the electrolyte includes a first electrolyte layer including a first polymer, a first lithium salt, and a first particle inorganic material having an average particle diameter (D50) of less than 500 nm; and a second electrolyte layer including a second polymer, a second lithium salt, and a second particle inorganic material having an average particle diameter (D50) of 500 nm or greater, wherein the first electrolyte layer is disposed in a direction facing the anode.