Template-free synthesis of α-Ni(OH)2 hollow microspheres with flower-like morphology for high-performance supercapacitors

Hollow electrode materials are of great charm due to their large surface area, low density, and superior structure permeability. The paper reported a new method for synthesis of alpha-Ni(OH)(2) hollow microspheres not using any soft- or hard template. The alpha-Ni(OH)(2) was prepared in the mixed solvent of tert-butanol (TBA) and water (H2O) by one-step hydrothermal synthesis. The structure of alpha-Ni(OH)(2) depends on the ratio of TBA/H2O. When the volume ratio of TBA/H2O is about 9:1, the alpha-Ni(OH)(2) exhibits hollow microsphere with flower-like morphology. The unique structure will greatly improve the faradaic redox reaction and mass transfer. The alpha-Ni(OH)(2) electrode displays excellent electrochernical performance for supercapacitors. Its specific capacitance is up to 2480.7 F g(-1) at 1 A g(-1). The capacitance can remain 91.6% at 10 A g(-1) after 1500 cycles. The study also provides a promising approach for building on hollow nanomaterials for supercapacitor, Li-ion battery and other energy storage devices. (C) 2014 Elsevier Ltd. All rights reserved.