Hollow NiSe/CoSe/Co(OH) hexagonal plates for high-performance hybrid supercapacitors

In order to improve the electrochemical performance, the combination of different battery-like electrode materials has attracted tremendous attention. Herein, a synthetic strategy has been proposed by combining Ni 0.85 Se, Co 0.85 Se and Co(OH) 2 materials. With nickel-cobalt hydroxide as the precursor, hollow Ni 0.85 Se/Co 0.85 Se/Co(OH) 2 hexagonal plates were successfully synthesized. When investigated as electrode materials for supercapacitors, outstanding electrochemical performance of the Ni 0.85 Se/Co 0.85 Se/Co(OH) 2 electrode is achieved by taking advantage of the high specific capacitance of Ni 0.85 Se and Co 0.85 Se, preferable cycling stability of Co(OH) 2 and special hollow architecture. The Ni 0.85 Se/Co 0.85 Se/Co(OH) 2 electrode demonstrates a high specific capacitance of 842.7 F g −1 after 2000 cycles at the current density of 2 A g −1 and the Ni 0.85 Se/Co 0.85 Se/Co(OH) 2 //AC hybrid supercapacitor device shows a remarkable specific energy of 48.9 W h kg −1 at a specific power of 569.4 W kg −1 . Hollow Ni 0.85 Se/Co 0.85 Se/Co(OH) 2 hexagonal plates were prepared by controlling the selenylation reaction rate between Ni-Co hydroxide and Se, and the composite showed outstanding cycling stability and satisfactory specific energy and specific power.