Study on the Electrochemical Property of Microporous Cobalt Phosphite [Co-11(HPO3)(8)(OH)(6)]

Abstract

Crystalline microporous cobalt phosphite, Con (HP03)8(OH)6, was prepared via facile hydrothermal route without the use of any templates or surfactants. The cobalt chloride hexahydrate (CoC12 center dot 6H20) and sodium hypophosphite monohydrate (NaH2P02 center dot 1420) were employed as reactants, and sodium bicarbonate (NaHCO3) was added to adjust the pH. The resultant Con (HP03)8(OH)6 shows dumbbell -like shape with a size of several micrometers. The obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), field -emission scanning electron microscopy (FE-SEM), and energy dispersive spectrometry (EDS). The Coli(HP03)8(OH)6 is applied as electrochemical energy storage electrode material because of its unique microporous nature. Different aqueous electrolytes (LiOH, NaOH, and KOH) have been tested in order to study the effect of electrolyte cations on electrochemical behavior. To investigate the capacity and stability of Coll(HP03)8(OH)6 electrode, cyclic voltammetry (CV), galvanostatic charge -discharge (GC), and cycle stability were performed in aqueous electrolytes with different cations at room temperature. We found that the electrochemical behavior of these materials is strongly dependent on the species of electrolyte cations (Li+, Na+, and K+).