Spinel Oxide Surface Layer for Lithium Battery Cathode Stability
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Solution Overview
Problem
Lithium batteries with high voltage and high capacity cathode active materials experience degradation due to side reactions at high temperatures and voltages, leading to performance degradation.
Innovation Solution
The use of an electrode active material with a lithium-free oxide surface treatment layer having a spinel structure, which acts as a protective layer to prevent side reactions and transition metal eruption, is applied to the core capable of occluding and emitting lithium, enhancing stability under high temperature and voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high voltage and high capacity cathode active materials are used, then energy density and performance are improved, but side reactions occur at high temperature and voltage leading to battery degradation
Solution Approach 1:
A surface treatment layer comprising lithium-free spinel oxide is introduced as an intermediary between the cathode active material core and the electrolyte. This intermediate layer prevents direct contact and harmful interactions while allowing lithium ion transport, thereby resolving the contradiction between achieving high energy density through high voltage materials and maintaining battery reliability by preventing side reactions at elevated temperatures and voltages
Solution Approach 2:
The electrode active material is designed as a composite structure consisting of a core cathode active material (such as LiCo1/3Mn2/3O4 or LiNi0.8Co0.1Mn0.1O2) and a surface treatment layer of lithium-free spinel oxide (such as MgAl2O4 or ZnAl2O4). This composite structure combines the high capacity characteristics of the core material with the protective and stabilizing properties of the spinel oxide surface layer, enabling both high energy density and improved thermal stability
2Quantity of substance
If high voltage cathode materials are used to increase energy density, then capacity is improved, but transition metal elution and gas generation occur causing performance degradation
Solution Approach 1:
The lithium-free spinel oxide surface treatment layer serves as a protective intermediary that physically blocks the elution of transition metals from the cathode core material into the electrolyte. This intermediate barrier layer maintains the structural integrity of the high capacity core material while preventing harmful metal ion release, thus resolving the contradiction between achieving high capacity and preventing transition metal elution
Solution Approach 2:
The surface treatment process converts the potential harm of high voltage-induced material instability into a benefit by forming a stable spinel oxide surface layer. This surface layer, which is inherently stable at high voltages, transforms the vulnerable core material into a protected structure that can operate at high voltages without eluting transition metals or generating gas, thereby converting the high voltage condition from a harmful factor into an enabling condition for high capacity operation
Data Source
AI summary
An electrode active material, a method of manufacturing the same, and an electrode and a lithium battery adopting the same. The electrode active material includes a core capable of occluding and emitting lithium; and a surface treatment layer formed on at least a portion of a surface of the core, wherein the surface treatment layer includes a lithium-free oxide having a spinel structure.