Hydrothermal synthesis of manganese phosphate/graphene foam composite for electrochemical supercapacitor applications

• Published in: Journal of colloid and interface science 2017-05, Vol.494, p.325-337
• Main Authors: Mirghni, Abdulmajid Abdallah, Madito, Moshawe Jack, Masikhwa, Tshifhiwa Moureen, Oyedotun, Kabir O., Bello, Abdulhakeem, Manyala, Ncholu
• Format: Article
• Language: English
• Subjects: Activated carbon; Asymmetric supercapacitor; Energy storage; Graphene foam; Hydrothermal method; Manganese phosphate
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2017.01.098

[Display omitted] Manganese phosphate (Mn3(PO4)2 hexagonal micro-rods and (Mn3(PO4)2 with different graphene foam (GF) mass loading up to 150mg were prepared by facile hydrothermal method. The characterization of the as-prepared samples proved the successful synthesis of Mn3(PO4)2 hexagonal micro-rods and Mn3(PO4)2/GF composites. It was observed that the specific capacitance of Mn3(PO4)2/GF composites with different GF mass loading increases with mass loading up to 100mg, and then decreases with increasing mass loading up to 150mg. The specific capacitance of Mn3(PO4)2/100mg GF electrode was calculated to be 270Fg−1 as compared to 41Fg−1 of the pristine sample at a current density of 0.5Ag−1 in a three-electrode cell configuration using 6M KOH. Furthermore, the electrochemical performance of the Mn3(PO4)2/100mg GF electrode was evaluated in a two-electrode asymmetric cell device where Mn3(PO4)2/100mg GF electrode was used as a positive electrode and activated carbon (AC) from coconut shell as a negative electrode. AC//Mn3(PO4)2/100mg GF asymmetric cell device was tested within the potential window of 0.0–1.4V, and showed excellent cycling stability with 96% capacitance retention over 10,000 galvanostatic charge-discharge cycles at a current density of 2Ag−1.