High Li-Ion Conductivity in Li{N(SO₂F)₂}(NCCH₂CH₂CN)₂ Molecular Crystal

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• The development of advanced solid electrolytes is crucial for next-generation energy storage devices.
• Organic molecular crystals are promising candidates for solid electrolytes, but achieving high ionic conductivity remains a challenge.

Purpose of the Study:

• To report a novel molecular crystal with exceptionally high lithium-ion conductivity.
• To evaluate its performance as a solid electrolyte in all-solid-state lithium-ion batteries.

Main Methods:

• Synthesis and characterization of a new Li{N(SO2F)2}(NCCH2CH2CN)2 molecular crystal.
• Measurement of ionic conductivity at various temperatures.
• Fabrication and testing of an all-solid-state lithium-ion battery using the developed electrolyte.

Main Results:

• The Li{N(SO2F)2}(NCCH2CH2CN)2 crystal exhibited a high Li-ion conductivity of 1 × 10^-4 S cm^-1 at 30 °C and 1 × 10^-5 S cm^-1 at -20 °C.
• The material demonstrated a low activation energy of 28 kJ mol^-1.
• The all-solid-state Li-ion battery showed stable cycling, retaining 90% of its initial capacity after 100 cycles.

Conclusions:

• The novel molecular crystal offers one of the highest Li-ion conductivities reported for organic crystals.
• This finding significantly advances the potential of molecular crystals as solid electrolytes for high-performance, safe all-solid-state lithium-ion batteries.