Achieving High Energy High Power Density in a Flexible Quasi Solid State Sodium Ion Capacitor.
Simultaneous integration of high energy output with high power delivery is a major challenge for electrochemical energy storage systems, limiting dual fine attributes on a device. We introduce a quasi solid state sodium ion capacitor (NIC) based on a battery type urchin like Na2Ti3O7 anode and a capacitor type peanut shell derived carbon cathode, using a sodium ion conducting gel polymer as electrolyte, achieving high energy high power characteristics in solid state. Energy densities can reach 111.2 Wh kg( 1) at power density of 800 W kg( 1) and 33.2 Wh kg( 1) at power density of 11200 W kg( 1) which are among the best reported state of the art NICs. The designed device also exhibits long term cycling stability over 3000 cycles with capacity retention ~86% Furthermore, we demonstrate the assembly of a highly flexible quasi solid state NIC and it shows no obvious capacity loss under different bending conditions.
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