Preparation and electrochemical performances of Co_χNi_{(1 − χ)}(OH)₂ coated carbon nanotube free standing films as flexible electrode for supercapacitors

Abstract

Co_χNi_{(1 − χ)}(OH)₂ nanocomposites have been deposited onto the carbon nanotube (CNT) films via a facile chemical deposition method. The introduction of Co element can effectively boost the property of the composite electrodes by changing the morphology of oxides and the combination mode between oxides and CNT bundles. The specific capacitance of composite electrode doped with 5% Co is 1231 F g^− 1 at 1 A g^− 1, which is almost twice than that without Co (725 F g^− 1). Furthermore, the electrochemical performance of the oxides in the electrode is significantly enhanced from 1823 to 3436 F g^− 1 with the introduction of 5% Co. In addition, the ultrahigh cycling stability of the composite electrode is fully proved by the remarkable drop of the capacitance loss from 15% to 2.3% with the addition of Co under 1500 times cycling at 10 A g^− 1. All indicating such composite is a highly promising candidate as electrode material.

Keywords:

• Hybrid hydroxides
• Co_χNi_{(1 − χ)}(OH)₂
• CNT films
• Supercapacitors