Overlithiated Composite Cathode for High-Voltage Lithium Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium batteries face challenges in achieving high voltage, high specific energy, and high-density performance while maintaining improved lifespan and capacity characteristics, particularly during repeated charge and discharge cycles.
Innovation Solution
A composite positive electrode active material is developed, comprising an overlithiated layered oxide with a molar ratio of vanadium to magnesium at 1:2, which is synthesized by mixing metal, vanadium, and magnesium precursors, followed by drying and heat treatment with a lithium precursor, to enhance structural stability and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional positive active materials are used to achieve high voltage and high specific energy, then energy density is improved, but lifespan and capacity characteristics deteriorate during repeated charge and discharge cycles
Solution Approach 1:
The patent applies composite materials by combining multiple metal elements (nickel, cobalt, manganese, vanadium, magnesium) in specific ratios to create a composite oxide material. This composite structure allows the material to achieve high voltage and specific energy while the synergistic effect of different elements maintains structural stability during charge-discharge cycles, thereby improving lifespan characteristics.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the molar ratios of metal elements (Ni: 0.1-0.3, Co: 0.1-0.3, Mn: 0.3-0.5, V: 0.01-0.05, Mg: 0.01-0.05) and the lithium excess parameter (0.05-0.15). These parameter optimizations enable the material to achieve high specific energy while maintaining structural integrity during cycling, resolving the contradiction between energy density and lifespan.
2Use of energy by moving object
If high voltage operation is implemented to improve energy density, then specific energy is improved, but structural stability deteriorates leading to capacity reduction
Solution Approach 1:
The patent applies local quality by introducing vanadium and magnesium elements at specific local positions within the crystal structure to stabilize the high-voltage phase. These elements are strategically positioned to maintain structural stability during high-voltage operation, allowing the material to achieve high energy density without sacrificing structural integrity.
Solution Approach 2:
The patent employs beforehand cushioning by pre-introducing vanadium and magnesium elements into the crystal structure before high-voltage operation. These elements act as structural buffers that prevent phase transitions and maintain stability during high-voltage charging, thereby preserving both energy density and structural stability.
3Quantity of substance
If conventional materials are used to achieve high capacity, then specific energy is improved, but capacity retention deteriorates upon repeated cycling
Solution Approach 1:
The patent applies merging by combining multiple functional elements (nickel for high capacity, cobalt for stability, manganese for structural support, vanadium for voltage stabilization, and magnesium for phase maintenance) into a single composite material system. This merging allows the material to achieve high capacity while maintaining excellent capacity retention through the synergistic effects of all elements.
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 improves the lifespan and capacity retention of lithium secondary batteries by stabilizing the oxidation-reduction reaction during charge and discharge, particularly at high voltages, leading to enhanced battery performance.
Implementation Method 1
drying the precursor mixture to form a dried mixture
Implementation Method 2
heat treating the dried mixture and the lithium precursor to manufacture the composite positive electrode active material
Data Source
AI summary
A composite positive electrode active material including: an overlithiated layered oxide (OLO) including vanadium (V) and magnesium (Mg), wherein the vanadium and magnesium have a molar ratio of about 1:2. Also a method of manufacturing the composite positive electrode active material, a positive electrode including the composite positive electrode, and a lithium battery including the positive electrode.