Porous carbon-wrapped cerium oxide hollow spheres synthesized via microwave hydrothermal for long-cycle and high-rate lithium-ion batteries

Porous hollow structures have attracted tremendous interests due to their geometrical beauty, unique structural features and fascinating physicochemical properties. In the present work, we developed a general procedure for the synthesis of hollow nanostructured carbon-wrapped cerium oxide (CeO2/C) via a microwave hydrothermal process without any surfactants or hard templates. The electrochemical performances of CeO2/C specimen were tested as anode materials in lithium ion batteries. The results showed that CeO2/C hollow spheres exhibited an exceptional cyclic stability with a high reversible capacity of 313 mA h g−1 after 500 cycles at a high current density of 1000 mA g−1 without signs of further degradation and also presented an excellent rate performance from 1000 to 10000 mA g−1. The improved performances were attributed to the homogeneous carbon with 3D network structure in hollow spheres and the Ce3+ in the oxygen-deficient fluorite-like CeO2-x on the surface of ceria nanoparticles, which enhanced the conductivity of CeO2 hollow spheres, suppressed the aggregation of active particles and reduced the apparent activation energy to facilitate the kinetics of Li+ insertion-extraction. The unique hollow structure of CeO2 wrapped by conductive carbon have made CeO2 a promising candidate for future applications in various metal oxide electrodes to mitigate the mechanical degradation and capacity fading, critical for developing advanced electrochemical energy storage systems with long-cycle life and high-rate performance.