Flexible supercapacitors based on mesoporous nanocrystalline cobalt ammonium phosphates and bacterial cellulose composite electrode

A flexible electrode of NH4CoPO4 · H2O composite bacterial cellulose (Co-BC) has been successfully prepared via a hydrothermal method. A bacterial cellulose (BC) membrane was used as a host matrix for nanocrystalline (NC) NH4CoPO4 · H2O. The preparation process included anchoring nanocrystalline NH4CoPO4 · H2O on BC nanofibers with an intrinsic 3D network structure. X-ray diffraction (XRD) results indicated the orthorhombic structure of the NH4CoPO4 · H2O NC within the Pmn21 space group and BC of a Type-I structure. FE-SEM images revealed microplate-like NH4CoPO4 · H2O structures on BC nanofibers. The a three-electrode system of all samples were studied for their electrochemical properties by CV, charge/discharge and EIS estimations in a 3 M KOH electrolyte. A maximal specific area capacitance of 158.5 mF cm−2 (43.3 F g−1) was obtained at a current density of 0.25 mA cm−2 using a Co-BC90 electrode. Moreover, this sample show an excellent capacitance retention of 99% after a 3000 cycle at 1 mA cm−2 current density.