Solid-liquid battery
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Solution Overview
Problem
Existing lithium batteries face challenges with low energy density, poor cycle performance, and safety issues due to voltage resistance limitations of ether electrolytes, and high impedance and complexity of solid electrolytes.
Innovation Solution
A solid-liquid battery design with a lithium metal negative electrode, using a solid electrolyte sandwiched between a high-voltage positive electrode and a lithium metal electrode, where ether and ester electrolyte solutions are used to improve compatibility and reduce impedance, while incorporating additives to enhance safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If ether electrolyte solution is used, then cycle performance of lithium negative electrode is improved, but voltage resistance is poor and decomposition occurs at high voltage
Solution Approach 1:
The battery is divided into two distinct compartments: a first battery containing ether electrolyte solution with lithium metal negative electrode, and a second battery containing ester electrolyte solution with high-voltage positive electrode. This segmentation allows each electrolyte to operate in its optimal voltage range, resolving the contradiction between cycle performance and voltage resistance.
Solution Approach 2:
A solid electrolyte is introduced as an intermediary component between the positive and negative electrodes. This solid electrolyte acts as a mediator that enables ion transport while providing physical isolation, allowing the system to achieve both high cycle performance and voltage resistance by preventing direct contact between electrolytes and electrode materials.
2Reliability
If ester electrolyte solution is used, then voltage resistance is improved, but coulombic efficiency for lithium metal is low and cycle life is limited
Solution Approach 1:
The battery system is segmented into two separate battery units, each optimized for specific electrolyte types. The first battery uses ether electrolyte solution for high coulombic efficiency with lithium metal, while the second battery uses ester electrolyte solution for high voltage resistance, thereby resolving the contradiction between voltage resistance and cycle life.
Solution Approach 2:
Different electrolyte solutions are applied to different regions of the battery system based on local requirements: ether electrolyte solution is used where high coulombic efficiency is needed (with lithium metal negative electrode), while ester electrolyte solution is used where high voltage resistance is needed (with high-voltage positive electrode).
3Reliability
If solid electrolyte is used, then safety is improved and dendrite short circuit is prevented, but energy density is reduced due to high density
Solution Approach 1:
The battery employs a segmented architecture with separate first and second batteries connected in series. This segmentation allows the solid electrolyte to be used only where safety is critical (preventing dendrite penetration), while liquid electrolytes are used in other regions to maintain high energy density, thus resolving the contradiction between safety and energy density.
Solution Approach 2:
The invention changes the physical state parameter of the electrolyte from entirely solid to a combination of solid and liquid phases. By using solid electrolyte only in specific locations where safety is paramount and liquid electrolytes elsewhere, the system achieves both improved safety and maintained energy density.
4Reliability
If solid-solid interface is used between solid electrolyte and electrode, then safety is improved, but interface impedance increases and process complexity increases
Solution Approach 1:
A protective film is introduced as an intermediary layer between the solid electrolyte and the electrode materials. This film mediates the interface interaction, reducing impedance and improving compatibility while maintaining the safety benefits of the solid electrolyte structure.
Solution Approach 2:
The interface structure is designed as a composite system combining solid electrolyte, protective film, and electrode materials. This composite approach optimizes both safety and electrical performance by combining the advantages of different materials at the interface.
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 design enhances cycle life and energy density by improving voltage resistance and reducing interface impedance, while ensuring safety through the use of fluorinated electrolytes and a protective lithium nitride layer, preventing decomposition and explosion.
Implementation Method 1
the existence of the solid electrolyte can completely prevent the influence of metal ions (nickel ions or manganese ions) dissolved from the electrolyte of high-nickel ternary or manganese-based lithium-rich positive electrode materials on the performance of the negative electrode after migrating to the surface of metal lithium
Implementation Method 2
a solid-liquid battery comprises a positive electrode and a negative electrode, the negative electrode is made of metal lithium, a solid electrolyte is provided between the positive electrode and the negative electrode
Data Source
AI summary
A solid-liquid battery includes a solid electrolyte provided between a positive electrode and a negative electrode made of metal lithium, an ester electrolyte solution is filled between the solid electrolyte and the positive electrode to increase the selection space of the positive electrode, and an ether electrolyte solution is filled between the solid electrolyte and the negative electrode to improve the cycle life of the lithium metal. By filling the electrolyte solution, the amount of the solid electrolyte used can be reduced, and the interface impedance of the battery can be reduced on the basis of ensuring that the safety is improved by using the solid electrolyte; furthermore, the existence of a solid electrolyte can prevent the influence of metal ions dissolved from the electrolyte on the performance of the negative electrode after migrating to the surface of lithium metal.