SiSe₂ for Superior Sulfide Solid Electrolytes and Li-Ion Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Layered silicon diselenide (SiSe2) exhibits unique properties due to its structure but remains unexplored for energy applications.
• Existing energy storage technologies require advanced materials for improved performance and safety.

Purpose of the Study:

• To synthesize layered SiSe2 using a facile solid-state route.
• To investigate the potential of SiSe2 as an additive for sulfide solid electrolytes in all-solid-state batteries (ASSBs).
• To evaluate SiSe2 as an anode material for lithium-ion batteries (LIBs).

Main Methods:

• Solid-state synthesis of layered SiSe2.
• Fabrication and electrochemical evaluation of SiSe2-substituted Li-argyrodites as solid electrolytes for ASSBs.
• Testing of SiSe2 as an anode material in LIBs with ex situ analysis.

Main Results:

• SiSe2-substituted Li-argyrodites demonstrated high ionic conductivity, low activation energy, and excellent air stability.
• ASSB full cells using SiSe2-modified electrolytes achieved high capacity (202/169 mAh g^-1) and stable cycling.
• SiSe2 nanocomposite anodes exhibited high capacity (950/775 mAh g^-1), high initial Coulombic efficiency (81.6%), and robust cycling stability for LIBs.

Conclusions:

• Layered SiSe2 is a versatile material for energy storage applications.
• SiSe2 shows significant potential as both a solid electrolyte additive for ASSBs and an anode material for LIBs.
• The facile synthesis and promising electrochemical performance highlight SiSe2's viability for future energy devices.