Spherically Structured Ce-Metal-Organic Frameworks with Rough Surfaces and Carbon-Coated Cerium Oxide as Potential Electrodes for Lithium Storage and Supercapacitors

Abstract

The rough spherical-shaped cerium metal-organic framework (Ce-MOF) is synthesized by using solvothermal technique, and after being calcined at 550 degrees C both with and without tannic acid, CeO2 and C@CeO2 are produced. As synthesized Ce-MOF, CeO2, and C@CeO2 are constructed as anodes for lithium-ion batteries (LIBs), also Ce-MOF and C@CeO2 are investigated for use in supercapacitors. In the case of LIBs, as anode, C@CeO2 exhibits a good reversible discharge capacity of 137 mAh g(-1) with 99 % coulombic efficiency over 250 cycles at 1 C rate. It demonstrates that the conductivity is greatly improved by the carbon covering than the pristine CeO2 and Ce-MOF. After the galvanostatic charge- discharge technique at 1 C rate, the morphology size was investigated using FESEM to conform further the following alloying and dealloying mechanism of C@CeO2 and the dissolution of terephthalic acid (TPA) in the non-aqueous electrolyte that is connected to the core structure of Ce-MOF. In terms of supercapacitors, rough surface morphology improves the electrode electrolyte conduct also the ligand TPA of free terminal acid group attracting K+ and forms the COO- K+. Thus, Ce-MOF exhibits a good specific capacitance; after 5000 cycles, it produces 118 F g(-1) at 4 A g(-1).with 65.2 % capacitance retention. The archived maximum power and energy density outcomes of 10.6 kW kg(-1) and 0.56 Wh kg(-1) at 2 A g(-1).