Structure, morphology and capacitance characteristics of Mn2(OH)3Cl obtained by the controlled droplet rate precipitation

Divalent manganese is difficult to exist in alkaline solution because it is extremely easy to be incompletely oxidized to trivalent. But it can be achieved by controlled its processing method. The basic manganese chloride (Mn2(OH)3Cl) was prepared by the controlled droplet rate precipitation method, and the controlled droplet rate of sodium hydroxide solution was 1.0 ​mL ​min−1. Hydroxylamine hydrochloride was added as a reducing agent in the preparation process to prevent the oxidation of the product and influence its purity. The composition, structure and morphology of the basic manganese chloride were characterized by X-ray diffraction (XRD), infrared spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy. The XRD analysis confirmed that the product was a single phase and its crystal structure belonged to orthorhombic system with cell parameters a ​= ​6.502 ​Å, b ​= ​9.487 ​Å, and c ​= ​7.071 ​Å. The SEM images showed that the basic manganese chloride crystals obtained by this method was a cube formed by overlapping sheets square pieces with a side length of about 1 ​μm. Electrochemical tests revealed that the capacitance of the Mn2(OH)3Cl/C/Ni electrode was 187.6 ​F ​g−1 when it was charged and discharged with a current of 0.2 ​A ​g−1, and its capacitance was 14.3 ​F ​g−1 when electrode was charged and discharged with a current of 3.0 ​A ​g−1. The manuscript describes the preparation, structure and capacitance characteristics of the novel basic manganese chloride. Electrochemical tests revealed that the product particles will be a promising electrode material for application in capacitors. [Display omitted] •Pure cubic Mn2(OH)3Cl was prepared by the controlled droplet rate precipitation.•Mn2(OH)3Cl was characterized by XRD, FTIR, SEM and XPS.•The capacitance of Mn2(OH)3Cl was much larger than that of Mn(OH)2.•The Mn2(OH)3Cl particles may have promising application in capacitors.