Dense Nanoparticle Electrode Layers for Li-Ion Microbatteries
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Solution Overview
Problem
Current methods for manufacturing dense ceramic layers for lithium ion microbatteries are costly, difficult to implement industrially, and prone to cracking, with existing techniques either requiring high temperatures or resulting in low energy storage capacities due to porosity and thickness limitations.
Innovation Solution
A method involving the use of non-agglomerated nanoparticles with specific size distributions, deposited using electrophoretic or coating techniques, followed by mechanical compression and/or low-temperature heat treatment to achieve dense, high-density layers with minimal porosity, suitable for use as electrodes or electrolytes in lithium ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating techniques (roll coating, doctor blade coating, tape casting, slot-die coating) are used with particles of 5-15 μm diameter, then layers of 50-400 μm thickness can be produced, but the layers remain porous (40% porosity) and require high temperatures for sintering, which increases manufacturing complexity and cost
Solution Approach 1:
The patent changes the particle size parameter from conventional 5-15 μm to nanometric scale (50-200 nm), which fundamentally alters the packing density and eliminates porosity without requiring high-temperature sintering. This parameter change enables dense layers to be formed through simple deposition and drying processes, resolving the contradiction between layer density and manufacturing complexity
Solution Approach 2:
The patent segments the particle size distribution into two distinct populations: a first population (50-200 nm) providing dense packing, and a second population (1-5 μm) providing structural integrity. This segmentation allows the layer to achieve both high density and mechanical strength without complex manufacturing processes
2Power
If particle size is reduced to improve power density, then diffusion rate increases, but layer thickness must be reduced which limits energy storage capacity
Solution Approach 1:
The patent transitions from a single particle size dimension to a dual-population size distribution, enabling the system to simultaneously achieve high power density (through nanometric particles) and high energy capacity (through thicker layers enabled by the bimodal distribution). The smaller particles provide rapid diffusion while the larger particles enable greater thickness
Solution Approach 2:
The patent creates a composite particle system with two distinct size populations that work synergistically: the nanometric particles (50-200 nm) provide high ionic conductivity and rapid lithium diffusion for power density, while the larger particles (1-5 μm) enable increased layer thickness for energy storage capacity
3Power
If porosity is increased to improve lithium ion diffusion, then power density increases, but energy density decreases due to reduced active material content
Solution Approach 1:
The patent changes the fundamental parameter of particle size from micrometric to nanometric scale, which eliminates the need for porosity to achieve good ionic conductivity. The nanometric particles provide such rapid diffusion pathways that dense, non-porous layers achieve both high power and energy density simultaneously
4Manufacturing precision
If high temperatures are used for sintering to densify layers, then layer density improves, but manufacturing cost increases and cracking may occur
Solution Approach 1:
The patent changes the particle size parameter to nanometric scale, which enables dense layer formation through simple deposition and drying without requiring high-temperature sintering. This parameter change eliminates the need for costly and complex thermal processing while avoiding cracking issues
Solution Approach 2:
The patent replaces the thermal sintering process with a mechanical/physical deposition process using nanometric particles. Instead of using heat to densify the layer, the patent uses the inherent packing properties of nanometric particles to achieve dense layers through low-temperature deposition and drying, eliminating the need for high-temperature equipment and reducing manufacturing complexity
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 method enables the production of dense, high-ionic conductivity layers with stable mechanical structures and long service life, suitable for lithium ion microbatteries, while avoiding the limitations of existing technologies such as high costs and cracking issues.
Implementation Method 1
The suspension is deposited, in particular by electrophoretic deposition
Implementation Method 2
The layer thus obtained is dried
Implementation Method 3
The dried layer is densified by mechanical compression and/or heat treatment
Implementation Method 4
The dried layer is densified by mechanical compression and/or heat treatment
Data Source
AI summary
A method for manufacturing a dense layer that includes: supplying a substrate and a suspension of non-agglomerated nanoparticles of a material P; depositing a layer on the substrate using the suspension; drying the layer thus obtained; and densifying the dried layer by mechanical compression and/or heat treatment. The method is characterised in that the suspension of non-agglomerated nanoparticles of material P includes nanoparticles of material P having a size distribution having a value of D50. The distribution includes nanoparticles of material P of a first size D1 between 20 nm and 50 nm, and nanoparticles of material P of a second size D2 characterised by the value D50 being at least five times less than that of D1, or the distribution has a mean size of nanoparticles of material P less than 50 nm, and a standard deviation to mean size ratio greater than 0.6.