Dual-Layer Positive Electrode with Halide-Sulfide Electrolytes
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Solution Overview
Problem
Existing lithium secondary batteries face challenges with side reactions between solid electrolytes and positive electrode active materials, which reduce ionic conductivity and hinder high-power and lifetime performance.
Innovation Solution
A positive electrode comprising a first positive electrode layer with a halide-based solid electrolyte and a second positive electrode layer with a sulfide-based solid electrolyte, each containing conductive materials and binders, is used to reduce side reactions and enhance ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in the positive electrode to eliminate leakage risk, then battery safety is improved, but resistance increases due to side reactions with the positive electrode active material
Solution Approach 1:
The positive electrode is segmented into two layers with different solid electrolytes. The first layer uses a solid electrolyte optimized for safety and stability with the active material, minimizing side reactions. The second layer uses a solid electrolyte optimized for low resistance and high ionic conductivity. This segmentation resolves the contradiction between safety and resistance by distributing these competing requirements to different layers.
Solution Approach 2:
The positive electrode employs a composite structure combining two different solid electrolyte materials, each with complementary properties. The first solid electrolyte provides safety and stability, while the second solid electrolyte provides low resistance and high ionic conductivity. This composite approach allows the electrode to simultaneously achieve both safety and low resistance, resolving the technical 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 electrode configuration improves battery performance by reducing resistance and enhancing ionic conductivity, resulting in improved high-power and lifetime characteristics.
Implementation Method 1
the first solid electrolyte and the second solid electrolyte are different from each other... improving ionic conductivity
Data Source
Figure 1
AI summary
The present invention relates to a positive electrode for a secondary battery and a secondary battery comprising the same, and more specifically, to a positive electrode for a secondary battery comprising a first positive electrode layer and a second positive electrode layer.