Facile synthesis of MnPO4•H2O nanosheets/MWCNTs composite as electrode material for high-performance supercapacitors

We report the fabrication of high stable manganese phosphate (MnPO4 center dot H2O) nanosheets MnPO4 center dot H2O/MWCNTs nanocomposites by a one-step facile hydrothermal synthesis followed by an annealing process. XRD results confirm that pure and composites show a monoclinic structure with a space group of C-2/c (Z = 4). SEM and TEM images reveal that the disordered structure made of nanosheets with a lateral dimension of 100-150 nm and a thickness of ca. 10-15 nm can be observed in pristine MnPO4 center dot H2O. Raman spectra again prove that monoclinic phases of MnPO4 center dot H2O and presence of MWCNTs in the MnPO4 center dot H2O/MWCNTs composite. The Pore Size and Surface distribution are studied through BET analysis, and the results show that the MnPO4 center dot H2O/MWCNTs composite shows highest specific area (135 m(2) g(-1)) and lower pore size 7.8 nm (compared to pristine MnPO4 center dot H2O). The XPS result reveals that Mn is 2(+) in a state in the spinel MnPO4 center dot H2O. The MnPO4 center dot H2O/MWCNTs composite delivers the capacity of about 765 F g(-1) at a specific current of 2 A g(-1) and capacity retention of about 94% after 5000 cycles. This study opens a new window for the fabrication of phosphate based materials for supercapacitors applications.