Carbon Matrix Dendrite-Intercepting Layer for Alkali Metal Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium metal and sodium metal batteries face significant challenges due to dendrite formation and penetration, which leads to internal shorting and safety issues, limiting their energy density and cycle life, especially in lithium-sulfur and sodium-sulfur cells operating at room temperature.
Innovation Solution
A dendrite penetration-resistant layer composed of an amorphous carbon or polymeric carbon matrix with carbon or graphite reinforcement phases, chemically bonded with lithium or sodium-containing species, is implemented between the metal anode and the separator to prevent dendrite growth and penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal or sodium metal is used as the anode active material to achieve high specific energy, then the specific energy of the battery is improved, but dendrite formation and penetration occur leading to internal shorting and safety issues
Solution Approach 1:
A dendrite-intercepting layer is introduced as an intermediary component between the alkali metal anode and the separator. This layer acts as a mediator that allows ionic conduction while physically intercepting and stopping dendrite growth, thereby maintaining the high specific energy benefits of metal anodes while preventing safety issues caused by dendrite penetration.
Solution Approach 2:
The dendrite-intercepting layer is constructed as a composite material system comprising a carbon matrix (amorphous or polymeric) reinforced with carbon or graphite particles, fibers, or flakes. This composite structure provides both the flexibility needed for ion transport and the mechanical strength to stop dendrites, resolving the contradiction between maintaining high energy density and ensuring safety.
2Reliability
If a rigid solid protective layer or ceramic material-based layer is used to stop dendrite penetration, then dendrite penetration is prevented, but the layer exhibits low ion conductivity and is difficult and expensive to manufacture
Solution Approach 1:
Instead of using rigid ceramic layers, the invention employs a flexible carbon-based dendrite-intercepting layer that can be manufactured as a thin film. This flexible carbon matrix structure is easier to manufacture, has higher ion conductivity, while still providing effective dendrite interception through its composite reinforcement structure.
3Reliability
If graphite is used as the anode to replace lithium metal, then safety is improved, but the specific energy is reduced
Solution Approach 1:
The anode system is segmented into two functional components: the alkali metal layer provides high capacity for ionic storage, while the dendrite-intercepting carbon layer provides safety by stopping dendrite growth. This segmentation allows the system to achieve both high specific energy from the metal and safety from the carbon intercepting layer.
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 solution significantly enhances the specific energy of alkali metal batteries to above 500 Wh/kg, while ensuring long cycle life and safety by effectively stopping dendrite penetration, thus overcoming the limitations of existing technologies.
Implementation Method 1
an amorphous carbon or polymeric carbon matrix and particles (e.g. thin fibers or platelets) of an optional carbon or graphite reinforcement phase dispersed in the carbon matrix, which are chemically bonded by a lithium- or sodium-containing species to form an integral layer
Implementation Method 2
a dendrite-intercepting layer implemented between a Li or Na layer and a separator layer
Implementation Method 3
chemically bonded by a lithium- or sodium-containing species to form an integral layer that prevents dendrite penetration
Data Source
AI summary
A rechargeable alkali metal battery comprising: (a) an anode comprising an alkali metal layer and a dendrite penetration-resistant layer comprising an amorphous carbon or polymeric carbon matrix, an optional carbon or graphite reinforcement phase dispersed in this matrix, and a lithium- or sodium-containing species that are chemically bonded to the matrix and/or the optional carbon or graphite reinforcement to form an integral layer that prevents dendrite penetration, wherein the lithium- or sodium-containing species is selected from Li2CO3, Li2O, Li2C2O4, LiOH, LiX, ROCO2Li, HCOLi, ROLi, (ROCO2Li)2, (CH2OCO2Li)2, Li2S, LixSOy, Na2CO3, Na2O, Na2C2O4, NaOH, NaX, ROCO2Na, HCONa, RONa, (ROCO2Na)2, (CH2OCO2Na)2, Na2S, NaxSOy, or a combination thereof, wherein X═F, Cl, I, or Br, R=a hydrocarbon group, x=0-1, y=1-4; (b) a cathode; and (c) a separator and electrolyte component; wherein the dendrite penetration-resistant layer is disposed between the alkali metal layer and the separator.