Hollow Ni0.85Se/Co0.85Se/Co(OH)2 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 Ni0.85Se, Co0.85Se and Co(OH)2 materials. With nickel–cobalt hydroxide as the precursor, hollow Ni0.85Se/Co0.85Se/Co(OH)2 hexagonal plates were successfully synthesized. When investigated as electrode materials for supercapacitors, outstanding electrochemical performance of the Ni0.85Se/Co0.85Se/Co(OH)2 electrode is achieved by taking advantage of the high specific capacitance of Ni0.85Se and Co0.85Se, preferable cycling stability of Co(OH)2 and special hollow architecture. The Ni0.85Se/Co0.85Se/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 Ni0.85Se/Co0.85Se/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.