All-Solid-State Supercapacitors Based on Na+ Ion Composite Solid Polymer Electrolyte: Tailoring the Interface by Solvent Layer Approach

Abstract

The present investigation proposes a novel approach to improve the performance of all solid-state supercapacitors (ASSCs). These ASSCs having a composite solid polymer electrolyte membrane (CSPE) and high surface area activated carbon (~ 1800 m2/g) electrodes exhibit improved performance when a novel strategy of ‘solvent layer approach’ at the electrode-electrolyte interface is used. Applying a nominal amount of acetonitrile (~3-5μl/cm2) at the interface leads to higher values of specific capacitance (~260F-g-1 at 2V, 1 mA), coulombic efficiency ~ 99 % and stability at least up to ~ 10000 cycles. It is demonstrated that a stack of five such cells can power an 8V LED circuit for more than 30 minutes. Results suggest that these supercapacitors are predominantly electric-double layer type in nature.

Keywords: Solid-state supercapacitor, Composite polymer electrolyte, Solid polymer electrolyte, Electric double layer supercapacitor