Transforming CO2 into energy storage solutions: MnCO3/electrochemically exfoliated graphene hybrid for supercapacitors and lithium-ion batteries

Official URL: https://dx.doi.org/10.1007/s10800-024-02191-z

This study introduces a one-pot synthesis approach to fabricate MnCO3/electrochemically exfoliated graphene (EEG) hybrid material through an electrochemical synthesis route. Our approach involves the use of a sacrificial anode to induce electrochemical exfoliation of a graphite rod, while the electrolyte captures CO2 from the air to utilize it in the synthesis of MnCO3 through a simple and well-controlled route. The absence of any chemical carbon dioxide source in the solution stands as a significant advantage for MnCO3 production. This approach promotes the creation of a synergistic MnCO3/EEG hybrid, capitalizing on the advantages of both materials. In addition, this method offers a scalable and cost-effective approach to fabricate MnCO3/EEG hybrid. MnCO3/EEG was characterized and analyzed utilizing a variety of techniques, including Fourier transform infrared spectroscopy (FTIR), Raman Spectroscopy, X-Ray Diffractometry (XRD), thermal gravimetric analysis (TGA) and scanning electron microscope/ electron dispersive spectroscopy (SEM/EDS). Electrochemical properties of MnCO3/EEG hybrid structure were studied in a three-electrode configuration by using cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests. The produced hybrid material has been successfully employed in asymmetric supercapacitors as the positive electrode to check its energy storage capabilities. In a three-electrode electrochemical cell, the MnCO3/EEG hybrid structure exhibited a specific capacitance of 90.5 F g−1. Subsequently, when an asymmetric device was prepared and its performance was evaluated, it demonstrated a maximum energy density (E) of 15.7 Wh kg−1 and a power density (P) of 701 W kg−1. The cycling stability remained above 85% after 3000 cycles. Furthermore, the hybrid material exhibiting the highest performance in supercapacitor studies has been evaluated as an anode material for lithium-ion batteries. In line with this objective, a lithium-ion battery cell was prepared, and similar electrochemical tests were conducted. The same material demonstrated a high specific capacity of 1382 mAh g−1 in lithium-ion battery half-cell applications. The results could be evidence that the innovative synthesis method is a prominent candidate to produce cost-effective and high-quality hybrid structures for energy storage devices. Furthermore, it is worth noting that the methodology employed in this study holds the potential for broader applications, extending beyond MnCO3 and MnxOy.