Synthesis of nanostructured cerium oxide-decorated phosphorus-doped carbon matrix electrodes for hybrid supercapacitors

Efficient hybrid electrochemical energy storage systems are collectively essential to address the increasing demand for sustainable energy solutions. To meet this requirement, a hydrothermal method was used to successfully synthesise a CeO₂-anchored phosphate carbon network (PCN) nanocomposite. The prepared nanocomposite exhibits a core–shell structure, with the carbon network encapsulating CeO₂ nanoparticles. Analysis of nitrogen sorption isotherms revealed that the CeO₂@PCN nanocomposite possesses a mesoporous structure, achieving an impressive specific capacitance of 1530 F g⁻¹. Further investigation into the capacitance contribution revealed that the electrode behaviour is characterised by the intermixing of diffusion-controlled and non-faradaic capacitance processes. When integrated into a hybrid supercapacitor device with graphene oxide (GO), the nanocomposite displayed a noteworthy specific capacitance of 216 F g⁻¹ for 1.5 A g⁻¹ current density and 1.2 V of an extended working potential range. The CeO₂@PCN//GO hybrid supercapacitor demonstrated a power density of 753 W kg⁻¹ and a matching energy density of 36 Wh kg⁻¹. The electrochemical experiments demonstrate the significant potential of CeO₂@PCN nanocomposite for employment in cutting-edge energy storage devices.

CeO₂@PCN was prepared by simple hydrothermal and calcination approach.

The environmental impact of producing nanostructured cerium oxide and phosphorus-doped carbon materials raises questions about the sustainability of using such advanced materials in supercapacitors, considering the energy and resources required for their synthesis. The scalability and cost-effectiveness of integrating cerium oxide-decorated phosphorus-doped carbon matrix electrodes into commercial hybrid supercapacitors remain contentious, potentially limiting their widespread adoption despite their promising performance enhancements. Additionally, the long-term stability and potential degradation mechanisms of these nanostructured materials under real-world operating conditions are still not fully understood, posing significant challenges to their reliability and longevity in practical energy storage applications.