Electrolyte Engineering to Construct Robust Interphase with High Ionic Conductivity for Wide Temperature Range...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Unstable interphases in lithium metal batteries (LMBs) limit the use of high-capacity nickel-rich layered oxides (NCM811) at varying temperatures.
• Conventional carbonate electrolytes struggle to maintain interfacial stability and ion transport kinetics.

Purpose of the Study:

• To develop a bifunctional electrolyte additive (EAFP) that enhances interfacial stability and ion transport in LMBs over a wide temperature range.
• To create a stable electrode/electrolyte interphase for improved NCM811 cathode performance.

Main Methods:

• Incorporation of 1,3-propanesultone as an additive to create a tailored bifunctional electrolyte (EAFP).
• Characterization of the cathode-electrolyte interphase structure and properties.
• Electrochemical testing of Li||Li, Li||NCM811, and graphite||NCM811 cells across a wide temperature spectrum (-40°C to 60°C).

Main Results:

• The EAFP additive formed a robust cathode-electrolyte interphase with an inorganic inner layer and organic outer layer, enhancing mechanical stability and flexibility.
• The optimized interphase facilitated fast Li+ transport and suppressed electrolyte side reactions, leading to low overpotentials and stable cycling.
• Li||Li cells demonstrated a lifespan of 1000 hours at 30°C, and Li||NCM811 pouch cells operated stably from -40°C to 60°C.
• EAFP showed compatibility with LiFePO4 and LiCO2 cathodes, maintaining 67% retention after 1000 cycles.

Conclusions:

• The developed bifunctional electrolyte (EAFP) effectively regulates the electrode/electrolyte interphase, enabling stable and high-performance operation of lithium metal batteries under wide temperature conditions.
• This approach provides a pathway for developing all-weather lithium metal batteries for diverse applications.
• The electrolyte's broad compatibility with different cathode materials highlights its potential for next-generation energy storage solutions.