3D Porous Electrode Architecture for Microbatteries
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Solution Overview
Problem
Miniature batteries face limitations in energy and power capabilities due to constraints in ion and electron diffusion lengths, leading to suboptimal power densities and energy densities, and existing 3D bicontinuous porous electrodes can result in hemispherically shaped electrodes that do not fully utilize device volume.
Innovation Solution
A method for fabricating 3D porous electrode architecture using a lattice structure and a solid structure on a substrate, where the interstices are infiltrated with conductive materials to form scaffolds, allowing for controlled porosity and size, enabling conformal deposition of active materials and improved ion diffusion pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electrode width increases simultaneously with height during fabrication, then the device volume utilization improves, but the power performance degrades and areal density is limited
Solution Approach 1:
The fabrication process is segmented into two distinct stages: first forming the lattice structure with controlled porosity, then adding the solid structure to define lateral dimensions. This segmentation allows independent optimization of vertical height (for volume utilization) and lateral width (for power performance) without the constraints of simultaneous growth.
Solution Approach 2:
The lattice structure is formed preliminarily before the solid structure is added. This preliminary action establishes the vertical framework and porosity characteristics first, allowing subsequent lateral expansion to be controlled independently by the solid structure without affecting the already-established vertical dimensions.
2Ease of manufacture
If the nickel current collector grows isotropically during bottom-up deposition, then the fabrication process is simple, but the electrodes become hemispherically shaped and do not fully utilize device volume
Solution Approach 1:
Different regions of the electrode structure are given different properties: the lattice structure provides vertical growth with controlled porosity for volume utilization, while the solid structure provides lateral confinement for shape control. This local differentiation of structural roles enables both simple fabrication and optimal volume utilization.
Solution Approach 2:
The electrode structure transitions from isotropic hemispherical growth to an asymmetric configuration with distinct vertical and lateral components. The lattice structure dominates vertical extension while the solid structure controls lateral dimensions, creating an asymmetric shape that maximizes volume utilization without requiring complex fabrication.
3Power
If the characteristic ion and electron diffusion lengths are reduced, then the power density increases, but the energy density decreases substantially
Solution Approach 1:
The electrode structure transitions from two-dimensional planar geometry to three-dimensional hierarchical architecture with lattice and solid structures. This dimensional evolution creates shortened diffusion pathways in the vertical direction through the lattice, while the lateral solid structure maintains sufficient active material volume, thereby achieving both high power density and energy density.
Solution Approach 2:
The lattice structure introduces controlled porosity with specific pore sizes and distributions that facilitate rapid ion transport throughout the electrode volume. This porous architecture reduces effective diffusion lengths for ions while maintaining high active material content in the solid structure, resolving the trade-off between power and energy density.
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 method enables microbatteries with excellent power performance and cyclability at high C rates, achieving increased energy and power densities by optimizing electrode morphology and ion transport.
Implementation Method 1
The lattice structure and the solid structure are removed from the substrate, thereby forming first and second conductive scaffolds
Implementation Method 2
Interstices of the first lattice portion are infiltrated with a first conductive material and interstices of the second lattice portion are infiltrated with a second conductive material
Data Source
AI summary
A method of fabricating a 3D porous electrode architecture comprises forming a microbattery template that includes (a) a lattice structure comprising a first lattice portion separated from a second lattice portion on a substrate, and (b) a solid structure on the substrate including a separating portion between the first and second lattice portions. Interstices of the first lattice portion are infiltrated with a first conductive material and interstices of the second lattice portion are infiltrated with a second conductive material. Each of the first and second conductive materials fill the interstices to reach a predetermined thickness on the substrate. The solid structure and the lattice structure are removed from the structure, thereby forming first and second conductive scaffolds comprising a porosity defined by the lattice structure and having a lateral size and shape defined by walls of the solid structure.