Solid Solution Cathode Material for High Voltage Lithium Ion Batteries
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Solution Overview
Problem
Current lithium-ion batteries have low energy density, which is insufficient for electric vehicle applications, and existing cathode materials do not meet the required performance standards.
Innovation Solution
A new solid solution composite material with the formula αLiMVO4-βLiNi1-x-yCoxMnyO2 is developed, combining a cubic close-packed LiMVO4 structure with a hexagonal layered LiNi1-x-yCoxMnyO2 structure, allowing for adjustable working voltage and high energy density, synthesized through methods like solid-phase ball milling and calcination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional layered transition metal oxide LiNi1-x-yCoxMnymO2 is used as cathode material, then good structural flexibility and stability are achieved, but energy density is insufficient for electric vehicle requirements
Solution Approach 1:
The patent creates a composite material consisting of LiMVO4 inverse spinel particles dispersed within the LiNi1-x-yCoxMnymO2 layered structure. This composite approach combines the structural stability of the spinel phase with the high capacity of the layered phase, achieving both improved reliability and increased energy density through synergistic material combination
Solution Approach 2:
The invention introduces LiMVO4 spinel domains at specific locations within the layered cathode material to locally enhance structural stability. These spinel regions act as structural anchors that prevent degradation at critical sites while maintaining the overall high-capacity layered structure, thereby improving reliability without sacrificing energy density
2Quantity of substance
If energy density is increased to meet electric vehicle requirements, then battery performance is improved, but material structural stability may be compromised
Solution Approach 1:
By forming a composite of LiMVO4 and LiNi1-x-yCoxMnymO2 phases, the patent achieves high energy density from the layered component while the spinel component provides structural reinforcement. The intimate mixing and interaction between the two phases at the nanoscale ensures that the high-capacity layered structure is stabilized by the presence of the spinel phase, simultaneously achieving both goals
3Quantity of substance
If working voltage is increased to improve energy density, then battery energy output is enhanced, but electrochemical stability may be reduced
Solution Approach 1:
The patent creates regions with different electrochemical properties by dispersing LiMVO4 spinel particles within the layered cathode. The spinel regions provide high-voltage stability and act as protective zones that prevent excessive voltage-induced degradation, while the layered regions maintain high capacity. This local differentiation allows the material to operate at higher voltages with improved electrochemical stability
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 composite material enhances the energy density of lithium-ion batteries, offering improved electrochemical activity and high voltage performance, suitable for use as cathode materials in rechargeable lithium-ion batteries.
Implementation Method 1
the mixture is calcined under temperature of 300-1000° C. about 15-50 h to obtain the composite
Implementation Method 2
a new solid solution composite, and methods of its preparation... solid solution composite materials usable as cathode materials
Data Source
AI summary
Described herein are solid solution composites that are used as cathode materials for lithium-ion batteries. The solid solution composite of α LiMVO4-βLiNi1-x-yCoxMnyO2, in which LiMVO4 has cubic close-packed structure, LiNi1-x-yCoxMnyO2 has hexagonal layered structure, and both share an oxygen lattice fully or partly. The new solid solution materials have advantage for lithium-ion batteries that the working voltage of the composite is adjustable by controlling the molar ratio of α and β and have higher working voltage than current secondary battery materials.Also described herein are methods of preparing such composite.