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

Abstract 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 α-Ni(OH) 2 hollow microspheres not using any soft- or hard template. The α-Ni(OH) 2 was prepared in the mixed solvent of tert-butanol (TBA) and water (H 2 O) by one-step hydrothermal synthesis. The structure of α-Ni(OH) 2 depends on the ratio of TBA/H 2 O. When the volume ratio of TBA/H 2 O is about 9:1, the α-Ni(OH) 2 exhibits hollow microsphere with flower-like morphology. The unique structure will greatly improve the faradaic redox reaction and mass transfer. The α-Ni(OH) 2 electrode displays excellent electrochemical 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.