The morphology controlled growth of Co11(HPO3)8(OH)6 on nickel foams for quasi-solid-state supercapacitor applications

Abstract

In this study, Co₁₁(HPO₃)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 Co₁₁(HPO₃)₈(OH)₆ obtained at 160 °C after 12 h with a H₂O/DMF ratio of 1 : 1 shows improved electrochemical performance. The flower-like Co₁₁(HPO₃)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 Co₁₁(HPO₃)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.