Piezoelectric Negative Electrode Framework for Lithium Dendrite Control
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Solution Overview
Problem
Lithium metal batteries face issues with volume expansion and dendrite formation during charging and discharging, leading to reduced efficiency, cycle life, and safety risks due to sharp dendrites piercing the separator and causing short circuits.
Innovation Solution
A negative electrode plate with a piezoelectric framework that generates a polarization electric field directing lithium deposition from the surface to the current collector, using materials like piezoelectric polymers, ceramics, or monocrystals to control lithium deposition and suppress dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as negative electrode to increase energy density, then the energy density and working voltage of the battery are significantly increased, but lithium deposition causes volume expansion and forms lithium dendrite structures that affect efficiency, cycle life, and safety
Solution Approach 1:
A gel layer is introduced as an intermediary substance between the lithium metal negative electrode and the electrolytic solution. This gel layer acts as a mediator that regulates lithium ion deposition, preventing direct contact between lithium metal and electrolyte, thereby suppressing dendrite formation while maintaining high energy density benefits
Solution Approach 2:
The patent changes the physical and chemical parameters of the interface between lithium metal and electrolyte by introducing a gel layer with specific mechanical properties (softness, elasticity). This parameter change creates a controlled deposition environment that prevents rapid, uneven lithium ion accumulation, thus suppressing dendrite growth while preserving high capacity
2Productivity
If lithium ions deposit fast at some sites due to inhomogeneous current density and concentration, then the deposition speed increases, but sharp dendrite structures are formed that pierce the separator and cause short circuits
Solution Approach 1:
The gel layer serves as a mediator that distributes lithium ion flux uniformly across the deposition surface. It prevents localized rapid deposition by providing a compliant interface that equalizes current density, thereby maintaining high overall deposition speed while eliminating sharp dendrite formation
Solution Approach 2:
The gel layer promotes homogeneous lithium ion distribution and deposition across the entire electrode surface. By providing a uniform, compliant interface, it ensures even current density distribution, preventing localized hotspots where dendrites would form, while maintaining efficient overall deposition
3Quantity of substance
If lithium metal deposits and expands during charging, then the capacity increases, but the volume expansion causes structural instability and reduces cycle life
Solution Approach 1:
A flexible gel layer is applied as a thin film over the lithium metal surface. This flexible shell accommodates volume expansion during charging by deforming elastically rather than cracking, maintaining structural integrity and preventing electrode degradation, thus enabling high capacity with improved cycle life
Solution Approach 2:
The patent changes the mechanical parameters of the electrode structure by introducing a soft gel layer with appropriate elasticity and compliance. This parameter change allows the structure to dynamically adapt to volume changes during cycling, maintaining stability while accommodating high lithium capacity
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 solution effectively homogenizes lithium deposition, mitigates volume expansion, and enhances cycle performance and safety by controlling dendrite formation and maintaining structural integrity.
Implementation Method 1
A polarization electric field exists inside the negative electrode framework. A direction of the polarization electric field is directed from a surface of the negative electrode to the negative current collector. A material of the negative electrode framework includes at least one of a piezoelectric polymer, piezoelectric ceramic, or piezoelectric monocrystal.
Data Source
AI summary
A negative electrode plate includes a negative current collector, a lithium metal negative electrode, and a negative electrode framework. A polarization electric field exists inside the negative electrode framework. A direction of the polarization electric field is directed from a surface of the negative electrode to the negative current collector. A material of the negative electrode framework includes at least one of a piezoelectric polymer, piezoelectric ceramic, or piezoelectric monocrystal. The negative electrode plate can control lithium deposition sites, effectively suppress the growth of lithium dendrites, effectively mitigate volume expansion of the electrochemical device, and further improve cycle performance of the electrochemical device.