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 °C both with and without tannic acid, CeO 2 and C@CeO 2 are produced. As synthesized Ce‐MOF, CeO 2 , and C@CeO 2 are constructed as anodes for lithium‐ion batteries (LIBs), also Ce‐MOF and C@CeO 2 are investigated for use in supercapacitors. In the case of LIBs, as anode, C@CeO 2 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 CeO 2 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@CeO 2 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 .