The morphology controlled growth of Co(HPO)(OH) on nickel foams for quasi-solid-state supercapacitor applications

In this study, Co 11 (HPO 3 ) 8 (OH) 6 was fabricated via a facile solvothermal process. The product with different morphologies of spherical-like, rod-like, bundle-like and flower-like microstructures can be easily controlled by adjusting the amount of DMF. Furthermore, flower-like Co 11 (HPO 3 ) 8 (OH) 6 obtained at 160 °C after 12 h with a H 2 O/DMF ratio of 1 : 1 shows improved electrochemical performance. The flower-like Co 11 (HPO 3 ) 8 (OH) 6 can be directly used as an electrode, demonstrating an excellent specific capacity of 919.3 C g −1 (1532.2 F g −1 ) at 1 A g −1 , and its capacity retention can reach 71.3% at 20 A g −1 . The as-prepared Co 11 (HPO 3 ) 8 (OH) 6 //AC device delivers a higher energy density of 14.5 W h kg −1 and has an outstanding cyclic stability of 83.5% after 7800 cycles. Co 11 (HPO 3 ) 8 (OH) 6 microstructures with different morphologies growing on NF were synthesized under different conditions, and the flower-like sample presents excellent electrochemical properties.