A sandwich-type sulfur cathode based on multifunctional ceria hollow spheres for high-performance lithium–sulfur batteries
Despite prominent research efforts towards developing cathode materials for lithium–sulfur batteries, relatively little emphasis has been placed on constructing functional cathode architectures. Herein, ceria (CeO2) hollow spheres are prepared to fabricate the inside and outside structures of cathodes. A sandwich-type sulfur cathode, namely, a h-CeO2/sulfur-x-CNT/h-CeO2 cathode, is designed and fabricated by a simple layer-by-layer process. Due to its unique structural and compositional features, the h-CeO2/sulfur-0.8-CNT/h-CeO2 cathode delivers high specific capacities of 876, 761, and 644 mA h g−1 at 1C, 2C and 5C rates, and the capacity retentions are 85.7%, 87.8%, and 92.4%, respectively. During 100 test cycles, the material displays high coulombic efficiencies (above 99%) after the first cycle. More importantly, the cathode with a sulfur loading of 1.8 mg cm−2 also exhibits a stable cycling life up to 500 cycles at 1C with a capacity decay as low as 0.073% per cycle.