Bi-functionality of Mesostructured MnCO₂O₄ Microspheres for Supercapacitor and Methanol Electro-oxidation

Abstract

In this work, we describe the synthesis of hierarchically mesoporous MnCo2O4 microspheres via a urea-assisted co-precipitation method, followed by a post-annealing treatment in air. The stoichiometric amount of urea serves as a self-template to favor the self-assembly of hierarchically well-organized, 3D interconnected precursor carbonate microspheres under optimized reaction conditions. An electrode fabricated from micro/nano-structured MnCo2O4 delivers an excellent multi-functional electrochemical performance when used in supercapacitors and methanol electro-oxidations. The electrode exhibits a high specific capacitance of 1857 F/g at a 5 mV/s scan rate, and 97% capacitance retention after 5000 cycles. Also, as an electro-catalyst for methanol oxidation, it maintains an optimum current density up to 95 A/g. The superior electrochemical performance might be attributed to its three-dimensional interconnected porous architecture, which offers a rapid ion/electron transfer, and structural stability. The synthesis method adopted in the present study is simple, controllable, and easy to carry out at a production scale. Furthermore, the superior electrochemical performance of the as-obtained MnCo2O4 microspheres renders them a potential candidate for various energy applications.