Lithium Metal Negative Electrode Salt Coating for Stable SEI
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Solution Overview
Problem
Lithium secondary batteries face performance deterioration due to consumption of salt and additives in the electrolyte, leading to overvoltage and reduced rate characteristics, as these components are not effectively replenished during charging and discharging.
Innovation Solution
A negative electrode with a salt coating layer containing lithium salt and additives is applied between lithium thin films, allowing for replenishment of consumed electrolyte materials and stable formation of the Solid Electrolyte Interphase (SEI), thereby improving battery lifetime and preventing lithium sulfide shuttling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If salt and additive in the electrolyte are increased to form stable SEI, then the SEI formation is improved, but overvoltage occurs and rate characteristics are reduced
Solution Approach 1:
The patent applies preliminary action by pre-coating the lithium metal surface with salt and additive materials before battery operation. This preliminary coating serves as a reservoir that releases materials during charging/discharging cycles to maintain SEI stability without requiring excessive salt and additive in the bulk electrolyte, thereby avoiding overvoltage and maintaining good rate characteristics.
2Reliability
If salt and additive are continuously consumed during charging/discharging, then the SEI formation is maintained, but battery performance deteriorates over time
Solution Approach 1:
The patent implements discarding and recovering by designing a system where salt and additive materials are deliberately consumed (discarded) from the coating layer during SEI formation and maintenance, while the coating layer itself acts as a reservoir that continuously replenishes (recovers) these materials. This cyclic process maintains SEI stability throughout battery operation without depleting the bulk electrolyte, thereby extending battery lifetime.
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 salt coating layer effectively replenishes consumed electrolyte components, maintaining high coulombic efficiency and delaying battery performance deterioration by stabilizing the SEI, thus enhancing the lithium secondary battery's lifetime performance.
Implementation Method 1
the salt coating layer including the lithium salt and the additive is formed between a plurality of lithium thin films, so that when the lithium salt and the additive contained in the electrolyte are consumed, the lithium salt and the additive in the electrolyte can be replenished from the lithium salt and the additive contained in the salt coating layer
Implementation Method 2
the lithium salt and the additive contained in the electrolyte can be replenished from the lithium salt and the additive contained in the salt coating layer
Implementation Method 3
The SEI may be formed by reacting lithium metal with a salt and an additive contained in the electrolyte
Implementation Method 4
During the discharging of the lithium-sulfur secondary battery, an oxidation reaction of lithium occurs at the negative electrode and a reduction reaction of sulfur occurs at the positive electrode
Implementation Method 5
the lithium ion conductivity of the lithium negative electrode can be improved
Data Source
AI summary
A negative electrode for a lithium secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same are provided. The negative electrode comprises a plurality of lithium thin films and a salt coating layer, which contains a lithium salt and an additive, formed between the plurality of lithium thin films, and provides improved lifetime characteristics of a battery while maintaining high coulombic efficiency because the lithium salt and the additive being consumed in the electrolyte during operation of the battery are replenished as the salt coating layer dissolves.