Lithium Titanium Oxide Coated Cathode for All-Solid-State Battery
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Solution Overview
Problem
Side reactions occur between the positive electrode active material and sulfide-based solid electrolyte particles in sulfide-based all-solid-state batteries, leading to consumption of active lithium and increased resistance.
Innovation Solution
A lithium titanium oxide particle layer is formed on the surface of the positive electrode active material, acting as a buffer to prevent these side reactions and enhance stability during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte particles are added to increase lithium ion conductivity, then ionic conductivity is improved, but side reactions occur at the interface consuming active lithium and increasing resistance
Solution Approach 1:
A lithium phosphate coating layer is applied to the surface of the positive electrode active material particles, serving as an intermediary barrier between the active material and sulfide-based solid electrolyte particles. This coating layer prevents direct contact and side reactions while maintaining lithium ion conductivity through the interface.
2Quantity of substance
If physical contact between positive electrode active material and sulfide-based solid electrolyte particles is increased to improve energy density, then energy density is improved, but side reactions are intensified
Solution Approach 1:
The lithium phosphate coating layer enables closer packing and increased physical contact between active material and electrolyte particles for higher energy density, while simultaneously acting as a protective intermediary that prevents harmful side reactions at the interface.
3Quantity of substance
If porosity of the positive electrode is reduced after rolling to improve energy density, then energy density is improved, but resistance increases due to reduced ion transport pathways
Solution Approach 1:
The lithium phosphate coating layer modifies the interfacial properties between particles, enabling reduced porosity and closer packing while maintaining low resistance through optimized interfacial lithium ion transport pathways. The coating layer parameters (composition, thickness) are controlled to balance density and conductivity.
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 lithium titanium oxide particle layer prevents side reactions, enabling stable charge and discharge of the all-solid-state battery while maintaining the bulk structure integrity of the positive electrode active material.
Implementation Method 1
the Li 4 Ti 5 O 12 particle layer can prevent side reactions between the positive electrode active material and the sulfide-based solid electrolyte particles during physical contact
Data Source
Figure 1
AI summary
The present disclosure relates to a positive electrode active material for an all-solid-state battery, a positive electrode, and an all-solid-state battery comprising same. More specifically, the positive electrode active material according to the present disclosure has a particle layer coated with lithium titanium oxide particles on its surface, wherein the particle layer prevents side reactions between the positive electrode active material and the sulfide-based solid electrolyte particles in the positive electrode, thereby enabling the all-solid-state battery to be stably charged and discharged.