Spherical Triclinic LiVOPO4 Nanoparticles for Battery Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Orthorhombic LiVOPO4 crystals used in lithium-ion secondary batteries suffer from decreased capacity upon repeated charging and discharging, while triclinic LiVOPO4 crystals have inferior crystal symmetry and lower rate characteristics due to poor Li-ion conductivity.
Innovation Solution
A triclinic LiVOPO4 crystal particle with a spherical form and average particle size of 20 to 200 nm, a BET specific surface area of 2 to 50 m2/g, and a longer to shorter diameter ratio of 1 to 2 is used, manufactured through hydrothermal synthesis to enhance cycle and rate characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If orthorhombic LiVOPO4 crystals are used to improve rate characteristic, then Li-ion conductivity is enhanced, but cycle characteristic deteriorates due to capacity decrease upon repeated charging and discharging
Solution Approach 1:
The invention changes the crystal system parameter from orthorhombic to triclinic, and simultaneously changes the particle size parameter to the nanometer range (20-200 nm). This dual parameter change resolves the contradiction by selecting a crystal structure that inherently provides better cycle stability while the nanoscale dimension ensures fast ion transport pathways, achieving both improved rate and cycle characteristics
2Reliability
If triclinic LiVOPO4 crystals are used to improve cycle characteristic, then stability is enhanced, but rate characteristic deteriorates due to inferior Li-ion conductivity
Solution Approach 1:
The invention segments the crystal into nanometer-scale particles (20-200 nm), creating numerous short diffusion pathways for lithium ions. This segmentation overcomes the inherent slow ion conductivity of triclinic crystals by reducing the total distance ions must travel, thereby achieving fast rate characteristics while preserving the cycle stability benefits of the triclinic structure
3Speed
If particle size is reduced to improve rate characteristic, then Li-ion diffusion is accelerated, but surface area increases causing more unnecessary reactions with electrolytic solutions
Solution Approach 1:
The invention optimizes the particle size to a specific nanometer range (20-200 nm) and controls the BET specific surface area within 2-50 m2/g. This precise parameter control achieves the optimal balance where particles are small enough to provide fast ion diffusion but not so small that excessive surface area causes harmful side reactions with the electrolyte
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 spherical triclinic LiVOPO4 crystal particles improve both cycle and rate characteristics by facilitating faster Li-ion diffusion and reducing unnecessary reactions with electrolytic solutions, resulting in a sufficient capacity and improved battery performance.
Implementation Method 1
speeding up Li-ion diffusion with a fine spherical particle having the above-mentioned average particle size employed as a triclinic LiVOPO4 crystal particle
Implementation Method 2
manufactured through hydrothermal synthesis to enhance cycle and rate characteristics
Data Source
AI summary
An active material contains a triclinic LiVOPO4 crystal particle, while the crystal particle has a spherical form and an average particle size of 20 to 200 nm.