Facile synthesis of bead-chain structured MWCNTs@CeO2 with oxygen vacancies-rich for promoting electrochemical energy storage

The extraordinary properties of metal oxides (MOs) have led to their increasing recognition as a potential material for energy storage systems, along with exceptional performance enhancement. Given the inherently finite electronic conductivity exhibited by most metallic oxides, commonly employed strategies to overcome this limitation involve their integration with conducting carbon materials or the introduction of oxygen vacancies. Herein, bead-chain structured MWCNTs@CeO2 with abundant oxygen vacancies (BC MWCNTs@Ov-CeO2) was successfully synthesized by utilizing chain-like MWCNTs to string together bead-like CeO2 nanoparticles, through a facile solvothermal approach. In particular, MWCNTs are neither covalently nor non-covalently modified, substantially simplifying fabrication procedures. The incorporation of carbon nanotubes and the abundance of oxygen vacancies effectively enhance charge storage dynamics, leading to significant improvements in conductivity and electrochemical properties beyond those previously reported CeO2-based composites. BC MWCNTs@Ov-CeO2 exhibited an impressive specific capacitance of 421.1 F g−1 at 1 A/g, outperforming pure CeO2 by 286%, demonstrating its superior capacitance performance. According to various theoretical and experimental investigations, it has been firmly established that the presence of conductive networks and oxygen vacancies significantly enhances the electrochemical properties of MOs. This research emphasizes the importance of understanding oxygen vacancies in electrode materials, providing a systematic approach for the development of future energy storage devices.