LixMeyOαFβ Positive Electrode with Insulating Layer for Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current battery technologies face challenges in achieving high capacity retention rates due to instability in crystal structures and increased resistance from side reactions with electrolytes, particularly in lithium-ion batteries.
Innovation Solution
A positive-electrode active material with a rock-salt-type crystal structure, represented by the composition LixMeyOαFβ, where Me includes various metals, and an insulating compound is used to maintain structural stability and prevent electrolyte decomposition, with the insulating compound present in limited amounts to avoid surface deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a positive-electrode active material with rock-salt-type crystal structure (LixMeyOαFβ) is used to increase Li intercalation and deintercalation capacity, then battery capacity increases, but crystal structure instability and side reactions with electrolyte increase, leading to decreased capacity retention
Solution Approach 1:
An insulating compound is introduced as an intermediary layer between the positive-electrode active material and the electrolyte. This insulating compound prevents direct contact and side reactions between the active material and electrolyte, thereby improving capacity retention while allowing the underlying active material to maintain high Li intercalation and deintercalation capacity.
Solution Approach 2:
The positive electrode is constructed as a composite material system combining the rock-salt-type active material (LixMeyOαFβ) with an insulating compound. This composite structure leverages the high capacity characteristics of the active material while the insulating compound provides structural stability and prevents electrolyte decomposition, achieving both high capacity and good capacity retention.
2Reliability
If the insulating compound is increased to prevent electrolyte decomposition and improve capacity retention, then capacity retention rate increases, but electrode surface deactivation occurs, reducing battery performance
Solution Approach 1:
The amount of insulating compound is precisely controlled within a specific range (0.1-5 mass%). This parameter optimization ensures sufficient protection against electrolyte decomposition and maintenance of capacity retention, while preventing excessive insulating material from blocking active sites and causing surface deactivation that would reduce battery performance.
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 enables lithium-ion batteries to maintain a high capacity retention rate and improved cycle characteristics by stabilizing the crystal structure and reducing resistance, allowing for higher Li intercalation and deintercalation without electrolyte decomposition.
Implementation Method 1
an insulating compound is used to maintain structural stability and prevent electrolyte decomposition
Implementation Method 2
allowing for higher Li intercalation and deintercalation without electrolyte decomposition
Data Source
AI summary
A positive-electrode active material contains a compound that has a crystal structure belonging to a space group FM3-M and contains is represented by the composition formula (1) and an insulating compound,LixMeyOαFβ (1)wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr, and the following conditions are satisfied.1.7≤x≤2.20.8≤y≤1.31≤α≤2.50.5≤β≤2