One-pot synthesis of the flower-like Co0.85Se nanosheets as an anode material for long-life aqueous asymmetric supercapacitor

Abstract

Flower-like Co0.85Se nanosheets were synthesized by Diethylenetriamine (DETA) and N-N-dimethylformamide (DMF) by a one-pot solvothermal method. The as-prepared Co0.85Se (VDETA/VDMF = 2/1) has a porous structure with a flower-like nanosheet. The flower-like Co0.85Se nanosheets exhibit high rate ability (73.2 % capacity retention from 0.5 A g−1 to 10 A g-1) and long cycle life, with about 83.3 % of the capacity retained after 10,000 cycles at 1A g-1. An activated carbon with a wide operating voltage window was selected as a negative electrode to assemble a Co0.85Se//AC ASC device. The Co0.85Se//AC ASC device with an operating voltage of 1.6 V shows an exceptionally long-life (91.67 % capacity retention after 50,000 cycles). Therefore, these flower-like Co0.85Se nanosheets with long cycle lives could be used as potential electrode materials in SCs.