Interfacial Assembled CeO<sub>2–<i>x</i></sub>/Co@N-Doped Carbon Hollow Nanohybrids for High-Performance Lithium–Sulfur Batteries
Wentao Qi, Wencai Yi, Wen Jiang, Rui Ling, Chao Yang, Shude Liu, Seong Chan Jun, Yusuke Yamauchi, Bingqiang Cao
Abstract
Despite their high theoretical specific energy, lithium–sulfur (Li–S) batteries still suffer from a significant shuttling effect and sluggish redox conversion of lithium polysulfides (LiPSs), which seriously hinders their practical application. Here, we develop a heterostructure comprising hollow oxygen-deficient CeO2 (H-CeO2–x)/Co nanocrystals@N-doped carbon (NC) nanospheres as a multifunctional sulfur host for Li–S batteries. The resulting H-CeO2–x/Co@NC effectively prevents the shuttling effect and accelerates trapping–diffusion–conversion of LiPSs through the interconnection of conductive networks and exposure of adsorptive/catalytic planes with different components. Theoretical calculations reveal that the introduction of oxygen vacancies and the formation of heterogeneous interfaces strengthen the combination of H-CeO2–x/Co@NC with LiPSs and accelerate the decomposition of Li2S. The introduction of Co induces an electric field in CeO2, which generates highly active interfaces to improve the adsorption ability and redox conversion for LiPSs. Consequently, the H-CeO2–x/Co@NC-sulfur cathode exhibits an outstanding rate performance (626 mAh g–1 at 5 C), superior cycling stability with a capacity retention of 81.6% after 1000 cycles at 2 C, and a high areal capacity of 5.3 mAh cm–2 at 0.1 C with a high sulfur loading (5.4 mg cm–2). This work provides insights for the rational design of heterostructures for high-performance Li–S batteries through interface control and defect chemistry.