Crosslinked Polymer Electrolyte for Lithium Metal Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries suffer from side reactions at high-voltage cathodes and the growth of lithium dendrites, leading to short circuits and deterioration, which current carbon-based anode materials fail to prevent effectively.
Innovation Solution
A lithium metal battery design incorporating a catholyte and anolyte with polymer electrolytes derived from single-ion conducting and crosslinking monomers, forming a strong crosslinked structure to suppress dendrite growth and prevent side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as anode active material to achieve high theoretical electrical capacitance (3860 mAh/g), then energy density is improved, but side reactions with electrolyte cause short circuit and deteriorate lifespan
Solution Approach 1:
A solid electrolyte interface (SEI) layer is formed on the lithium metal anode surface through electrolyte decomposition. This SEI layer acts as an intermediary barrier that prevents direct contact between the lithium metal and the electrolyte, thereby suppressing side reactions and electron transfer that would cause short circuits, while still allowing lithium ion transport during charging and discharging cycles
Solution Approach 2:
The electrolyte composition is modified by adjusting the ratio of cyclic carbonate (EC, PC) to chain carbonate (DMC, DEC) solvents, and by adding lithium salts such as LiPF6, LiBF4, or LiClO4. These parameter changes optimize the formation of a stable SEI layer on the lithium metal surface, improving both the electrochemical stability and the lifespan of the battery while maintaining high capacity
2Quantity of substance
If high-voltage cathode (3.5 V or more, 4.0 V or more) is used to improve energy density, then electrical capacitance is improved, but organic solvent in electrolyte is oxidized causing side reactions and deterioration
Solution Approach 1:
The electrolyte is formulated with a specific composition of cyclic carbonates (EC, PC) and chain carbonates (DMC, DEC) in optimized ratios, along with lithium salts. This parameter optimization raises the oxidation potential of the electrolyte, enabling it to withstand high-voltage cathodes (3.5V or 4.0V) without decomposition, thereby preventing side reactions and electrolyte deterioration while maintaining high energy density
Solution Approach 2:
A small amount of sacrificial additive (0.01-5 wt%) is included in the electrolyte that preferentially reacts with the high-voltage cathode surface to form a protective coating. This sacrificial component protects the main electrolyte from oxidation by consuming itself in controlled side reactions, thereby preventing harmful cumulative effects on battery lifespan
3Duration of action of moving object
If lithium-containing metal layer is plated or dissolved during charging and discharging, then electrochemical cycling is achieved, but impurities accumulate making the surface rough and hard
Solution Approach 1:
A protective coating layer is formed on the lithium-containing metal layer surface through controlled electrolyte decomposition or by applying a thin film of polymer electrolyte. This intermediary layer prevents direct exposure of the lithium metal surface to the bulk electrolyte, thereby reducing impurity accumulation and maintaining a smooth surface morphology during repeated charging and discharging cycles
Solution Approach 2:
The electrolyte composition is designed to self-heal minor surface defects on the lithium-containing metal layer during cycling. The controlled decomposition and reformation of the SEI layer during charge-discharge cycles automatically repairs surface irregularities, maintaining surface smoothness without external intervention
4Quantity of substance
If lithium dendrites are plated on rough and hard surface to achieve high capacity, then electrical capacitance is improved, but continuous growth causes short circuit between anode and cathode
Solution Approach 1:
The electrolyte composition parameters (solvent ratios, lithium salt concentration, additive content) are optimized to control the plating morphology of lithium dendrites. By adjusting these parameters, the electrolyte promotes uniform lithium deposition rather than dendritic growth, achieving high capacity while preventing short circuits through controlled electrochemical parameters
Solution Approach 2:
A protective SEI layer or polymer electrolyte coating serves as an intermediary between the lithium-containing metal layer and the bulk electrolyte. This intermediary layer provides a uniform interface that guides lithium ion deposition, preventing direct contact between growing dendrites and the electrolyte, thereby suppressing continuous dendrite growth and preventing short circuits while maintaining high 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 novel electrolyte structure enhances ion conductivity, reduces internal resistance, and improves cycle characteristics by preventing electrolyte deterioration and lithium dendrite growth, thereby extending battery lifespan.
Implementation Method 1
the first polymer includes a first repeating unit derived from a first single ion conducting monomer
Implementation Method 2
a second repeating unit derived from a first crosslinking monomer having a plurality of reactive functional groups
Implementation Method 3
crosslinking the applied composition for forming an anolyte to prepare the lithium metal anode coated with an anolyte
Implementation Method 4
crosslinking the injected composition for forming a catholyte to prepare a lithium metal battery including a catholyte
Data Source
AI summary
Disclosed are a lithium metal battery and a manufacturing method therefor, the lithium metal battery including a cathode, an anode, and an electrolyte disposed between the cathode and the anode, wherein the anode includes a lithium metal, the electrolyte includes a catholyte disposed adjacent to the cathode and an anolyte disposed between the catholyte and the anode, the catholyte includes a first polymer electrolyte, the first polymer electrolyte includes a first polymer, and the first polymer includes a first repeating unit derived from a first single-ion conducting monomer and a second repeating unit derived from a first crosslinking monomer having a plurality of reactive functional groups.