Organopolysiloxane Cathode Composition for Mn Leaching Control
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Solution Overview
Problem
Lithium manganese phosphate batteries face issues with manganese ion leaching during charging, leading to rapid capacity decay and safety concerns due to interfacial side reactions and electrolyte consumption.
Innovation Solution
A positive electrode material composition is developed, comprising a lithium manganese phosphate active material doped with specific elements at Li, Mn, P, and O sites, combined with an organopolysiloxane compound to reduce manganese leaching and enhance electrochemical performance, improving rate performance, cycling stability, and high-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium manganese phosphate is used as positive electrode active material, then high capacity and good safety performance are achieved, but manganese ion leaching occurs during charging resulting in rapid capacity decay
Solution Approach 1:
The patent introduces an organopolysiloxane compound as an intermediary substance that forms a protective interface layer between the lithium manganese phosphate particles and the electrolyte. This intermediary layer prevents direct contact and chemical reactions between the electrode material and electrolyte, thereby reducing manganese ion leaching while maintaining lithium ion transport efficiency.
Solution Approach 2:
The patent creates a composite material system consisting of lithium manganese phosphate particles coated with organopolysiloxane compound. This composite structure combines the high capacity properties of lithium manganese phosphate with the protective and stable properties of organopolysiloxane, achieving both high capacity and reduced capacity decay.
2Quantity of substance
If lithium manganese phosphate is used as positive electrode active material, then high capacity is achieved, but interfacial side reactions with electrolyte occur leading to safety concerns
Solution Approach 1:
The organopolysiloxane compound serves as a mediator that physically separates the lithium manganese phosphate from the electrolyte, preventing harmful interfacial side reactions while allowing beneficial lithium ion transport. The compound's molecular structure provides a barrier that blocks direct contact between the electrode material and electrolyte.
Solution Approach 2:
The patent converts the harmful effect of electrolyte contact into a beneficial protective mechanism. The organopolysiloxane compound, when exposed to the electrolyte, forms a stable protective layer that transforms the potentially harmful interfacial reactions into a beneficial protective interface that enhances safety while maintaining performance.
3Ease of manufacture
If lithium manganese phosphate is used as positive electrode active material, then abundant raw material sources are available, but manganese ion leaching results in rapid capacity decay
Solution Approach 1:
The organopolysiloxane compound acts as a mediator that preserves the advantages of lithium manganese phosphate (abundant raw materials, high capacity) while eliminating its main disadvantage (manganese leaching). The compound forms a protective barrier that prevents manganese ion release into the electrolyte during charging and cycling.
Solution Approach 2:
The patent changes the surface chemical parameters of lithium manganese phosphate by coating it with organopolysiloxane compound. This surface modification alters the chemical environment at the electrode-electrolyte interface, reducing the solubility and reactivity of manganese ions while maintaining the bulk material's high capacity properties.
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 solution effectively reduces manganese ion leaching, enhances specific capacity, and improves the overall electrochemical performance of lithium manganese phosphate batteries, leading to increased energy density and extended cycle life while maintaining high-temperature stability.
Implementation Method 1
the combination of the positive electrode active material with the organopolysiloxane compound of the present application can alleviate the erosion of the surface of the positive electrode active material caused by the electrolytic solution and reduce the leaching out of Mn and Mn-site doping elements
Implementation Method 2
Lithium manganese phosphate has become one of the most popular positive electrode active materials due to its high capacity
Data Source
AI summary
The present application provides a positive electrode material composition, a method for the preparation thereof and a positive electrode plate, a secondary battery and an electrical device containing the same. The positive electrode material composition includes a positive electrode active material and an organopolysiloxane compound, wherein said positive electrode active material has a chemical formula of LiaAxMn1-yByP1-zCzO4-nDn. The positive electrode material composition of the present application enables the secondary battery to have a relatively high energy density, while further improving rate performance, cycling performance and/or high-temperature stability of the secondary battery.