High specific surface area NiTiAl layered double hydroxide derived via alkali etching for high performance supercapacitor electrode

Abstract

As a simple and efficient approach, alkaline etching acquires high porosity and increases the specific surface area for Al containing layered double hydroxides Al containing to improve the specific capacity and rate performance. Herein, NiTiAl layered double hydroxide was synthesized by adding minute amounts of Al to the NiTi-LDH basal layer and then etched some Al using sodium hydroxide solution to obtain higher specific surface area, specific capacity, and rate performance of supercapacitor electrodes. The sample etched for 18 h acquires a high specific surface area up to 203 m2g-1 and the highest specific capacity of 3483 mF cm-2 under 5 mA cm-2, which is 86.58 m2g-1 and 933 mF cm-2 higher than the unetched sample, also acquires a better structural stability than NiTi layered double hydroxide. The same sample exhibits the best rate performance with the highest specific capacity of 2000 mF cm-2 at 30 mA cm-2, which is 57.4% of the specific capacity for the same sample tested at 5 mA cm-2 and 750 mF cm-2 higher than the unetched samples tested at 30 mA cm-2. A hybrid device assembled by the etched sample acquires a higher energy density of 45.1 Wh kg-1 and a power density of 16000 W kg-1.