Coated Positive Electrode Active Material Composite for Solid-State Batteries
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Solution Overview
Problem
Lithium-ion secondary batteries face issues of high interfacial resistance and low lithium-ion conductivity between the positive electrode active material and the sulfide-based solid electrolyte, leading to reduced lifespan and power output.
Innovation Solution
A positive electrode active material composite is developed, comprising a positive electrode active material substrate coated with a compound represented by Formula 1 (Li a Ti b O c-d X d ), where X is N, P, or S, to reduce interfacial resistance and enhance lithium-ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer of Li-M-O (M=B, Al, Zr, P, Ti, Nb, W, etc.) is formed on the surface of positive electrode active material, then the stability of the battery is improved, but the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte remains high
Solution Approach 1:
The patent changes the chemical composition parameters of the coating layer by introducing specific elements (Fe, Co, Ni, Cu, Zn, Mn, Ca, Sr, or Ba) with controlled content ratios (0.1-5 atom% each). This compositional parameter adjustment optimizes the coating layer's properties to simultaneously achieve stability and reduced interfacial resistance, resolving the contradiction between reliability improvement and resistance reduction.
Solution Approach 2:
The patent creates a composite coating layer structure combining traditional Li-M-O compounds with additional functional elements (Fe, Co, Ni, Cu, Zn, Mn, Ca, Sr, or Ba). This composite material approach integrates the stability-providing Li-M-O framework with elements that reduce interfacial resistance, allowing both requirements to be satisfied simultaneously through material composition synergy.
2Ease of manufacture
If conventional coating techniques are used on positive electrode active material, then the manufacturing process is simple, but the lithium ion conductivity between the positive electrode and solid electrolyte is insufficient
Solution Approach 1:
The patent modifies the coating layer's chemical composition by incorporating specific elements (Fe, Co, Ni, Cu, Zn, Mn, Ca, Sr, or Ba) at controlled concentrations (0.1-5 atom%). This parameter change enhances lithium ion conductivity while preserving the simplicity of conventional coating manufacturing processes, as the compositional adjustment can be achieved through standard mixing and coating techniques without complex process modifications.
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 composite effectively lowers interfacial resistance and improves lithium-ion conductivity, resulting in enhanced drive characteristics and life characteristics of the battery.
Implementation Method 1
The positive electrode active material composite of the present invention provides the effect of reducing the interfacial resistance between the positive electrode active material and the solid electrolyte by a coating layer formed on the surface of the positive electrode active material
Implementation Method 2
improving the lithium-ion conductivity, a positive electrode comprising the positive electrode active material composite
Data Source
AI summary
The present invention provides a positive electrode active material composite comprising a positive electrode active material substrate and a coating layer comprising a compound represented by Formula 1 below coated on the positive electrode active material substrate, a positive electrode comprising the positive electrode, and a lithium-ion secondary battery comprising the positive electrode. [Formula 1] LiaTibOc-dXd