Fabrication, structure, electrochemical properties, and enhanced pseudocapacitive performance of cobalt oxyhydroxide films via a simple strategy

Cobalt oxyhydroxide (CoOOH) has recently emerged as a promising electrode material for energy storage. Herein amorphous CoOOH and Mn-doped CoOOH films were prepared by anodic deposition, and the effect of Mn doping on the pseudocapacitive behaviors of CoOOH material was investigated. When tested in 1 M NaOH, the area specific capacitance ( C A , F cm −2 ) of CoOOH material can be increased by doping 7.59 at. % Mn due to much increased surface area. When tested in 1 M NaCl, the C A of 7.59 at. % Mn-doped CoOOH film increased with the increasing CV cycle number during ~ 100–1000 CV cycle, and became more and more larger than that of CoOOH film during 434–1000 CV cycle, which was mainly attributed to the increasing surface area during CV test. These indicated that surface area was a vital factor to improve the pseudocapacitive behaviors of CoOOH material. Consequently, depositing a fine nanostructured CoOOH film onto a conductive, porous and high surface area substrate is considered as an effective method to further improve its pseudocapacitive behaviors.