Enhancing the performance of solid-state supercapacitors using Li⁺-garnet polymer hybrids as electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state supercapacitors (SSCs) offer safer alternatives to liquid electrolyte devices.
• Developing high-performance electrolytes is crucial for advancing SSC technology.

Purpose of the Study:

• To synthesize and characterize Li+-ion garnet polymer composites for SSC electrolytes.
• To investigate the performance of SSCs utilizing these novel composite electrolytes.

Main Methods:

• Synthesis of Niobium-substituted cubic garnet LLZNO and its incorporation into a PEO matrix.
• Fabrication of SSCs with activated carbon electrodes and a micro-gel interface layer using DMF.
• Electrochemical characterization including ionic conductivity, capacitance, power, energy, and cycle life testing.

Main Results:

• Optimized electrolyte composition achieved high ionic conductivity (∼2 × 10^-4 Ω^-1 cm^-1 at 30 °C).
• SSCs exhibited a ∼3 V stability window, specific capacitance of ∼143 F g^-1, specific power of ∼1303 W kg^-1, and specific energy of ∼24 Wh kg^-1.
• Excellent capacitance retention (>53% after 100,000 cycles) and temperature tolerance (-10 °C to 50 °C) were observed.

Conclusions:

• The developed Li+-ion garnet polymer composite electrolytes are highly effective for high-performance SSCs.
• The micro-gel interface layer significantly enhances SSC performance.
• Demonstrated practical application by powering LEDs, highlighting the potential for reliable energy storage.