Porous Lithium Metal Anode Biasing for Dendrite Suppression
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Solution Overview
Problem
Lithium metal anodes in batteries face limitations due to dendrite formation and growth, leading to reduced longevity, potential short circuits, and volume changes during charging and discharging, which are exacerbated by high current densities and surface defects.
Innovation Solution
Incorporating a battery cell design with a porous anode structure and deposition biasing elements, such as seed layers and dendrite quenching layers, to bias ion deposition away from the separator, thereby inhibiting dendrite growth and maintaining homogeneous operation and reducing volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanically rigid electrolytes are used to inhibit dendrite growth, then dendrite formation is suppressed, but charging rate is limited due to ineffective confinement at high current densities
Solution Approach 1:
The patent applies different functional zones within the anode structure: a porous ion-conducting material layer for uniform ion distribution, and a mechanically rigid electrolyte layer for dendrite confinement. This local differentiation allows the porous structure to handle high current densities while the rigid layer suppresses dendrites, resolving the contradiction between charging rate and dendrite inhibition.
Solution Approach 2:
The anode combines porous ion-conducting materials (such as ceramic materials or polymers) with mechanically rigid electrolytes to create a composite structure. The porous material enables rapid ion transport for high charging rates, while the rigid electrolyte component provides mechanical confinement against dendrite growth, simultaneously achieving both objectives.
2Quantity of substance
If Li metal anode is used to achieve high capacity, then specific energy is increased, but dendrite formation and volume changes reduce longevity
Solution Approach 1:
The patent employs a porous ion-conducting material as the anode structure instead of dense Li metal. The porous architecture provides multiple benefits: it maintains high capacity by accommodating Li ions, reduces volume changes during cycling through its open structure, and prevents dendrite formation by distributing ion flux uniformly across the porous network, thereby improving longevity.
Solution Approach 2:
The patent changes the physical and chemical parameters of the anode by using ion-conducting materials with specific porosity, ion conductivity, and mechanical properties. These parameter optimizations enable the anode to achieve high capacity while maintaining structural stability and preventing dendrite formation over extended cycling, thus resolving the capacity-longevity tradeoff.
3Productivity
If high current density is applied to increase charging rate, then productivity is improved, but dendrite growth is accelerated
Solution Approach 1:
The patent creates local quality differentiation by using a porous ion-conducting material that distributes current density uniformly across its structure. This prevents localized high current density hotspots that would otherwise accelerate dendrite growth, allowing high overall charging rates without compromising dendrite inhibition.
Solution Approach 2:
The porous structure of the ion-conducting material provides multiple pathways for ion transport, distributing the current load across a larger effective surface area. This reduces peak current density at any single location, enabling high charging rates without triggering dendrite formation, thus resolving the productivity-reliability contradiction.
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 inhibits dendrite formation and growth, increases battery longevity, allows for higher charging rates, and maintains structural integrity by ensuring even ion distribution within the anode, reducing the risk of short circuits and performance degradation.
Implementation Method 1
bias ion deposition within the anode, during a charging process for the battery cell, away from the separator
Implementation Method 2
the anode includes an ion conducting material with a porous structure
Data Source
AI summary
A battery cell includes a current collector, separator, anode, and deposition biasing element. The anode is positioned between the current collector and separator, and includes an ion conducting ceramic material with a porous structure. The biasing element is positioned within the battery cell so as to bias ion deposition within the anode, during a charging process, away from the separator. A method for forming a battery cell includes electrospinning particles of material into a mesh to form an anode that includes an ionically conductive material. At least one biasing element is applied to at least one of the anode and a current collector. The anode is positioned between the current collector and a separator. The current collector and the separator are joined to the anode.