Achieving High-Energy–High-Power Density in a Flexible Quasi-Solid-State Sodium Ion Capacitor

• Published in: Nano letters Vol. 16; no. 9; pp. 5938 - 5943
• Main Authors: Li, Hongsen, Peng, Lele, Zhu, Yue, Zhang, Xiaogang, Yu, Guihua
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.09.2016
• Subjects: high-energy density; conducting gel polymer; energy storage; solid-state; Sodium ion capacitor; high-power density
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.6b02932

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.