Uniform P-Doped MnMoO₄ Nanosheets for Enhanced Asymmetric Supercapacitors Performance

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Manganese molybdate (MnMoO₄·H₂O) shows promise for supercapacitors but faces limitations in specific capacitance and conductivity.
• Transition metal oxides often struggle to achieve theoretical capacitance due to inherent properties.
• Phosphorus doping is a viable strategy to improve electrochemical performance in metal oxides.

Purpose of the Study:

• To synthesize phosphorus-doped MnMoO₄·H₂O nanosheets on nickel foam.
• To investigate the impact of phosphorus doping on the electrochemical properties of MnMoO₄·H₂O.
• To evaluate the performance of the doped material in an asymmetric supercapacitor device.

Main Methods:

• Hydrothermal synthesis of MnMoO₄·H₂O nanosheets on nickel foam.
• Gas-solid reaction method for phosphorus element doping.
• Electrochemical characterization including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
• Fabrication and testing of a P-MnMoO₄//AC asymmetric supercapacitor (ASC).

Main Results:

• Phosphorus doping successfully introduced phosphorus-metal bonds and oxygen vacancies in MnMoO₄·H₂O.
• The specific capacitance of P-MnMoO₄ reached 2.112 F cm⁻² (1760 F g⁻¹) at 1 mA cm⁻², a 3.2-fold increase compared to undoped MnMoO₄·H₂O.
• The P-MnMoO₄//AC ASC device exhibited a high energy density of 41.9 Wh kg⁻¹ at 666.8 W kg⁻¹ and 84.5% capacity retention after 10,000 cycles.

Conclusions:

• Phosphorus doping effectively enhances the electrochemical performance of MnMoO₄·H₂O for supercapacitor applications.
• The P-MnMoO₄ material demonstrates superior charge storage capacity and conductivity.
• The developed P-MnMoO₄ holds significant potential as a high-performance electrode material for next-generation supercapacitors.