Porous Electroactive Materials for All-Solid-State Battery Stability
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Solution Overview
Problem
All-solid-state batteries face challenges with low energy density due to void spaces and inflexibility in accommodating stresses, leading to issues like micro-cracking and delamination, especially with high-capacity electrode materials that undergo significant volumetric expansion and contraction.
Innovation Solution
The development of composite electrodes with porous solid-state electroactive materials that have internal pores to accommodate volumetric changes, minimizing outward expansion and micro-cracking, combined with an appropriate solid-state electrolyte and structural additives to enhance mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity electrode materials like silicon are incorporated to increase energy density, then the energy density of all-solid-state batteries is improved, but the material undergoes large volumetric expansion and contraction causing physical damage to solid-state components
Solution Approach 1:
The patent applies porous solid-state electroactive materials where the porous structure provides internal void space to accommodate volumetric expansion and contraction during lithiation and delithiation cycles. This prevents physical damage to the material and surrounding solid-state components while maintaining high capacity, directly resolving the contradiction between energy density and structural integrity.
Solution Approach 2:
The patent uses composite electrode structures combining porous electroactive materials with solid-state electrolytes and conductive additives. This composite approach allows the electroactive material to undergo volume changes while the composite structure maintains overall integrity and enables continuous ion transport, resolving the contradiction between high capacity and structural stability.
2Object-affected harmful factors
If solid-state electrolytes are used to eliminate thermal runaway risks, then safety is improved, but the inflexibility of solid-state components leads to micro-cracking and delamination under stress
Solution Approach 1:
The porous structure of the solid-state electroactive material accommodates volumetric changes during cycling, preventing stress concentration that would lead to micro-cracking in the inflexible solid-state electrolyte and electrode layers, thus maintaining reliability while preserving safety benefits.
Solution Approach 2:
The patent modifies the physical parameters of the electroactive material by creating a porous structure with controlled porosity (10-75%). This parameter change allows the material to flexibly accommodate volume changes, preventing the propagation of cracks through the solid-state components while maintaining the inherent safety advantages of solid-state electrolytes.
3Quantity of substance
If void spaces between solid-state particles are reduced to improve density, then energy density is improved, but the ability to accommodate stresses and strains is reduced
Solution Approach 1:
The patent introduces a controlled porous structure within the electroactive material particles themselves, rather than relying on interparticle void spaces. This internal porosity accommodates stress and strain during cycling while allowing for higher overall packing density, thus improving energy density without sacrificing stress accommodation capability.
Solution Approach 2:
The patent shifts the stress accommodation mechanism from the interparticle level (2D/3D void spaces between particles) to the intraparticle level (porous structure within particles). This dimensional shift allows for denser packing of particles while maintaining the ability to accommodate volumetric changes through the internal porous network.
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 approach increases energy density while reducing micro-cracking and delamination, enabling robust and high-performance all-solid-state batteries with improved mechanical stability and efficiency.
Implementation Method 1
large volume changes, including volume expansion and contraction, of high-capacity electrode materials comprising silicon during lithiation and/or delithiation
Implementation Method 2
Each particle of the plurality of particles has a plurality of internal pores formed therein. The plurality of internal pores of the solid-state electroactive material accommodate the volumetric expansion and contraction of the solid-state electroactive material inwardly so to minimize outward expansion of the plurality of particles
Data Source
AI summary
A composite electrode for use in an all-solid-state electrochemical cell that cycles lithium ions is provided. The composite electrode comprises a solid-state electroactive material that undergoes volumetric expansion and contraction during cycling of the electrochemical cell and a solid-state electrolyte. The solid-state electroactive material is in the form of a plurality of particles and each particle has a plurality of internal pores formed therewithin. Each particle has an average porosity ranging from about 10% to about 75%, and the composite electrode has an interparticle porosity between the solid-state electroactive material and solid-state electrolyte particles ranging from about 5% to about 40%. The intraparticle pores and the interparticle porosity accommodate the volumetric expansion and contraction of the solid-state electroactive material so to minimize outward expansion of the electroactive particles, micro-cracking of the solid-state electrolyte, and delamination within the electrochemical cell.