Hybrid Solid Electrolyte Coating for Low-Resistance Solid-State Cathodes
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Solution Overview
Problem
All-solid-state batteries face challenges with high interfacial resistance between electrodes and solid electrolytes, leading to reduced lithium ion reversibility and increased lithium metal precipitation, which can cause short circuits and decrease energy capacity.
Innovation Solution
A positive electrode active material coated with both an oxide-based and a sulfide-based solid electrolyte, featuring a Li(NixCoyMnz)O2 layer with a LiCoO2 surface, and a hybrid solid electrolyte with layers of different densities, reduces interfacial resistance and prevents lithium metal precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte layer is used in all-solid-state batteries, then safety and stability are improved, but interfacial resistance increases and ionic conductivity decreases
Solution Approach 1:
The patent uses a composite solid electrolyte layer comprising both oxide-based solid electrolyte particles and sulfide-based solid electrolyte particles. The oxide-based solid electrolyte provides safety and stability, while the sulfide-based solid electrolyte enhances ionic conductivity. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both high safety and high ionic conductivity simultaneously.
2Quantity of substance
If the thickness of the positive electrode layer is increased to increase battery capacity, then energy capacity is improved, but lithium metal precipitation increases and short circuit risk increases
Solution Approach 1:
The patent introduces a composite solid electrolyte layer as an intermediary between the positive electrode layer and the negative electrode. This intermediate layer effectively manages lithium ion flux and prevents lithium metal precipitation even when the positive electrode layer thickness is increased. The sulfide-based solid electrolyte particles in particular contribute to reducing interfacial resistance and preventing lithium deposition, thereby enabling high capacity without increasing short circuit risk.
3Power
If sulfide-based solid electrolyte is used to achieve excellent output characteristics, then power is improved, but hydrogen sulfide generation occurs causing safety issues
Solution Approach 1:
The patent merges oxide-based solid electrolyte and sulfide-based solid electrolyte into a composite structure. The oxide-based solid electrolyte component suppresses hydrogen sulfide generation and improves safety, while the sulfide-based solid electrolyte component maintains excellent output characteristics and ionic conductivity. The synergistic combination allows the battery to achieve high power output without the harmful effects of pure sulfide-based electrolytes.
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
This configuration improves lithium ion reversibility, reduces interfacial resistance, and prevents short circuits, enhancing the performance and cycle characteristics of all-solid-state batteries while lowering production costs.
Implementation Method 1
In the solid electrolyte, ions move through a solid lattice. As a result, the solid electrolyte has a lower ionic conductivity than a liquid electrolyte, in which ions move freely through a fluid
Implementation Method 2
a hybrid solid electrolyte with layers of different densities
Data Source
AI summary
The present invention relates to an all-solid-state battery that can reduce the interfacial resistance between the electrolyte and electrode and can minimize the precipitation of lithium metal on the electrode and, more specifically, to an all-solid-state battery comprising: a cathode (100) including a cathode active material having a Li(NixCoyMnz)O2 (wherein 0<x<1, 0<y<1, 0<z<1, and x+y+z=1) layer; an anode (300); and a hybrid solid electrolyte (200) located between the cathode (100) and the anode (300), wherein the hybrid solid electrolyte (200) includes at least two solid electrolyte layers having different densities.