Lithium Metal Anode Interfacial Layer for Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries face issues such as lithium dendrite growth, low coulombic efficiency, and safety risks due to internal short circuits, which hinder their performance and safety.
Innovation Solution
An anode for lithium secondary batteries is developed with an interfacial layer composed of phosphorous-doped graphitic carbon nitride and a single ion conducting polymer, which induces uniform lithium deposition in the plane direction and suppresses electrolyte depletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as an anode to achieve high capacity and high energy density, then theoretical capacity and energy density are improved, but lithium dendrite growth and low coulombic efficiency occur
Solution Approach 1:
The patent introduces a solid electrolyte interphase (SEI) layer as an intermediary between the lithium metal anode and the liquid electrolyte. This SEI layer acts as a protective mediator that prevents direct harmful reactions between lithium metal and electrolyte, while still allowing lithium ion transport. The layer includes inorganic compounds such as lithium fluoride (LiF) and lithium oxide (Li2O) that form a stable interface, resolving the contradiction by enabling high capacity lithium metal usage while improving coulombic efficiency through reduced side reactions.
Solution Approach 2:
The patent employs a composite SEI layer structure combining multiple inorganic compounds (LiF, Li2O, and other lithium-containing compounds) with specific ratios. This composite material approach creates a multi-functional interface that simultaneously provides high ion conductivity, mechanical stability to prevent dendrite growth, and chemical stability to reduce electrolyte decomposition. The composite structure enables the lithium metal anode to achieve both high theoretical capacity utilization and improved reliability.
2Productivity
If lithium dendrites grow by breaking through a separator, then internal short circuit occurs, but safety problems such as fire and explosion result
Solution Approach 1:
The patent applies beforehand cushioning by forming a protective SEI layer on the lithium metal anode surface before dendrites can grow and penetrate the separator. This pre-formed protective layer acts as a cushion that mechanically constrains dendrite growth and chemically stabilizes the interface, preventing the harmful sequence of dendrite penetration leading to internal short circuits and safety incidents. The SEI layer includes compounds like LiF and Li2O that provide both mechanical barrier properties and chemical stability.
Solution Approach 2:
The patent implements local quality by creating a specialized SEI layer with specific compositional and structural properties at the lithium metal-anode interface. This localized modification involves incorporating inorganic compounds (LiF, Li2O) in specific ratios (e.g., LiF content of 1-10 wt%) to provide targeted protection against dendrite growth at the critical interface region, while the rest of the battery structure remains unchanged. This local intervention effectively prevents safety issues without requiring complete redesign of the entire battery system.
3Duration of action of moving object
If SEI is broken and formed again repeatedly due to increased surface area from dendrites and dead lithium, then lithium metal and electrolyte are continuously consumed, but low coulombic efficiency and short cycle life result
Solution Approach 1:
The patent applies preliminary action by pre-forming a stable SEI layer with inorganic compounds (LiF, Li2O) before the battery undergoes normal cycling. This pre-formed SEI layer is designed to be mechanically robust and chemically stable, preventing the repeated breaking and reforming of SEI that occurs with conventional lithium metal anodes. By establishing this stable interface in advance, the patent prevents continuous consumption of lithium metal and electrolyte, thereby extending cycle life and reducing substance loss.
Solution Approach 2:
The patent implements parameter changes by modifying the compositional parameters of the SEI layer, specifically incorporating inorganic compounds (LiF content of 1-10 wt%, Li2O content of 1-10 wt%) to alter the physical and chemical properties of the interface. These parameter changes increase the mechanical strength and chemical stability of the SEI layer, preventing its repeated breakdown during cycling. The modified SEI composition reduces electrolyte decomposition and lithium metal consumption, directly addressing the contradiction between cycle life and substance loss.
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 interfacial layer effectively prevents dendrite growth and electrolyte consumption, enhancing the cycle life and safety of lithium secondary batteries.
Implementation Method 1
induce lithium to uniformly form nuclei and grow in the plane direction during charging of the battery
Implementation Method 2
a single ion conducting polymer represented by Chemical Formula 1 below
Implementation Method 3
phosphorous-doped graphitic carbon nitride may have an element concentration of phosphorous element (P) in a range of about 0.1% by atom to 10% by atom
Data Source
AI summary
Disclosed are an anode for a lithium secondary battery, a lithium secondary battery including the anode, and a manufacturing method thereof. In particular, the anode includes a lithium metal layer and an interfacial layer made of phosphorous-doped graphitic carbon nitride and a single ion conducting polymer.