Lithium Metal Battery Protective Layer for Dendrite Suppression
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Solution Overview
Problem
The growth of lithium dendrites on the negative electrode surface in lithium metal secondary batteries degrades ion transportability and poses safety risks, limiting the battery's life characteristics and safety.
Innovation Solution
Incorporating a protective layer on the negative electrode or solid electrolyte with a mixture of electrically non-conductive hexagonal boron nitride flakes and an ionomer containing a sulfur (S)-containing anionic group and fluorine (F) to enhance mechanical strength, ion transportability, and oxidation potential window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium secondary batteries use liquid electrolytes, then ionic conductivity is maintained, but safety issues arise from leakage and combustion risks
Solution Approach 1:
The patent employs solid electrolytes that undergo phase transitions at specific temperatures to maintain ionic conductivity while preventing leakage and combustion. The solid-state electrolyte material transitions between different crystalline phases to accommodate lithium ion transport without the safety hazards of liquid electrolytes.
Solution Approach 2:
The patent utilizes composite solid electrolyte materials combining multiple components to achieve both high ionic conductivity and enhanced safety. The composite structure integrates different solid electrolyte materials with complementary properties to prevent leakage and combustion while maintaining reliable ion transport.
2Quantity of substance
If lithium metal anodes are used to increase energy density, then capacity is improved, but dendrite formation causes short circuits and reduced lifetime
Solution Approach 1:
The patent applies local quality modification by creating uniform lithium deposition zones on the anode surface through optimized solid electrolyte interfaces. This localized control of lithium ion flux prevents dendrite formation while maintaining high capacity, ensuring both energy density and lifetime performance.
Solution Approach 2:
The patent implements preliminary action by pre-forming a stable solid electrolyte interface (SEI) layer before lithium deposition begins. This pre-established interface prevents uneven lithium accumulation and dendrite growth during subsequent cycling, thereby extending battery lifetime while preserving high energy density.
3Reliability
If solid electrolytes are used to improve safety, then leakage and combustion are prevented, but ionic conductivity and cycle stability are insufficient
Solution Approach 1:
The patent optimizes parameters of solid electrolyte materials including composition ratios, sintering temperatures, and grain size to achieve both high ionic conductivity and excellent cycle stability. By precisely controlling these parameters, the solid electrolyte maintains stable performance over thousands of cycles while ensuring safety.
Solution Approach 2:
The patent develops composite solid electrolyte systems combining multiple materials with different functional properties. This composite approach enhances both ionic conductivity for better cycle stability and maintains the intrinsic safety advantages of solid-state electrolytes by preventing leakage and combustion.
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 additive mixture improves the mechanical strength and ion transportability of the protective layer, inhibiting dendrite growth, ensuring a wider oxidation potential window and enhancing the battery's life characteristics and safety.
Implementation Method 1
have demonstrated high ionic conductivity and cycle stability
Implementation Method 2
lithium metal secondary battery that uses a lithium metal anode, a solid electrolyte, and a cathode
Data Source
Figure 1~2
AI summary
The present disclosure relates to a lithium metal secondary battery including a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode, wherein the lithium metal secondary battery further includes a protective layer interposed between the negative electrode and the separator, and the protective layer includes an additive, which is a mixture of hexagonal boron nitride (BN) flakes with an ionomer having a sulfur (S)-containing anionic group and fluorine (F), added thereto.