Hybrid Thin-Film Encapsulation for All-Solid-State Thin-Film Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Thin-Film Technology

Background:

• All-solid-state thin-film batteries are crucial for microdevices.
• Solid electrolytes and lithium anodes require protection from atmospheric moisture.
• Thin-film encapsulation is underdeveloped for these sensitive battery components.

Purpose of the Study:

• To develop and investigate a hybrid thin-film encapsulation structure.
• To assess the protective capabilities of the encapsulation against moisture.
• To evaluate the long-term stability and performance of encapsulated thin-film batteries.

Main Methods:

• Fabrication of a hybrid encapsulation structure: SiO/SiNO/a-SiN:H/Parylene.
• Measurement of the water-vapor transmission rate (WVTR) of the encapsulation.
• Testing the stability of encapsulated all-solid-state thin-film batteries under atmospheric conditions through charge/discharge cycling.

Main Results:

• The hybrid thin-film encapsulation achieved a WVTR of 4.9 × 10⁻³ g m⁻²·day⁻¹.
• Encapsulated batteries demonstrated stability after 30 days in air and 100 charge/discharge cycles.
• A high Coulombic efficiency of 99.8% was maintained after 100 cycles in air.

Conclusions:

• The hybrid SiO/SiNO/a-SiN:H/Parylene encapsulation effectively protects thin-film batteries.
• This encapsulation is suitable for various applications including flexible solar cells and e-papers.
• The developed encapsulation ensures long-term stability for thin-film batteries in ambient conditions.