Fabrication of Porous Electrodes for Zinc-Ion Supercapacitors with Improved Energy Storage Performance

Abstract

Zn-ion supercapacitors (ZICs) show high energy densities with long cycling life for use in electronic devices. Porous Zn electrodes as anodes for ZICs are fabricated by chemical etching process using optimized conditions. The structures, morphologies, chemical bonding states, porous structure, and electrochemical behavior are examined. The optimized porous Zn electrode shows a root mean square of roughness of 173 nm and high surface area of 153 mu m(2). As a result, ZIC using the optimized porous Zn electrode presents excellent electrochemical performance with high specific capacitance of 399 F g(-1) at current density of 0.5 A g(-1), high-rate performance (79 F g(-1) at a current density of 10.0 A g(-1)), and outstanding cycling stability (99 % after 1,500 cycles). The development of energy storage performance using synergistic effects of high roughness and high surface area is due to increased electroactive sites by surface functionalization of Zn electrode. Thus, our strategy will lead to a rational design and contribute to next-generation supercapacitors in the near future.