Single-pot hydrothermal synthesis of manganese phosphate microrods as a cathode material for highly stable flexible solid-state symmetric supercapacitors

• Published in: Synthetic metals Vol. 267; p. 116446
• Main Authors: Katkar, Pranav K., Marje, Supriya J., Pujari, Sachin S., Khalate, Suraj A., Deshmukh, Prashant R., Patil, Umakant M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.09.2020; Elsevier BV
• Subjects: Capacitance; Cathodes; Computer storage devices; Crystal structure; Current density; Electrochemical analysis; Electrode materials; Electrodes; Electrolytes; Energy storage; Flexible symmetric solid-state device; Flux density; Hydrothermal crystal growth; Hydrothermal method; Manganese; Manganese phosphate; Microrods; Morphology; Portable equipment; Sodium sulfate; Solid state; Stainless steels; Substrates; Supercapacitor; Supercapacitors; Synthesis; Thin film; Thin films; Supercapacitor; Manganese phosphate; Hydrothermal method; Microrods; Flexible symmetric solid-state device; Thin film
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2020.116446

[Display omitted] •A binder-free synthesis of microrods-like manganese phosphate thin films on SS substrate by one-pot hydrothermal method.•The flexible manganese phosphate solid-state symmetric device has been assembled with PVA-Na2SO4 gel-electrolyte.•The device gives high energy at power density of 11.7 Wh kg−1 and 1.41 kW kg−1, respectively with good specific capacitance 37 F g−1 at 0.1 mA cm−2.•The device shows long-term cycling stability with 99 % capacitance retention over 9000 GCD cycles at a current density of 0.8 mA cm−2.•The actual practical demonstration of manganese phosphate device shows lightning of 3 red LEDs for 5 min. Here, we report a binder-free synthesis of microrods-like manganese phosphate thin film over stainless steel substrate by a facile, single-pot hydrothermal method. The XRD analysis reveals that, the formation of manganese phosphate [Mn3(PO4)2] material of a monoclinic crystal structure. From SEM images observed microrods like morphology of manganese phosphate with an average width of ∼25 μm. The manganese phosphate electrode shows a better electrochemical performance with a specific capacitance of 145 F g−1 at 0.2 mA cm-2 current density in 1.0 M Na2SO4 electrolyte. Moreover, the flexible solid-state symmetric electrochemical energy storage device was assembled with PVA-Na2SO4 solid gel-electrolyte consists of manganese phosphate as anode and cathode electrode. The corresponding symmetric supercapacitor achieves a high energy density of 11.7 Wh kg−1 at a high power density of 1.41 kW kg−1 with an excellent specific capacitance of 37 F g−1 at 0.1 mA cm-2 current density. Manganese phosphate shows long-term electrochemical cyclic stability at a current density of 0.8 mA cm-2 for 9000 galvanostatic charge-discharge cycles with excellent capacitance retention (99 %). This excellent capacitive performance confirms that the manganese phosphate is promising material and fabricated flexible solid-state symmetric supercapacitor has high potential in the field of portable and bendable energy storage devices.