Spinel/Lithium-Rich Manganese Oxide Hybrid Nanofibers as Cathode Materials for Rechargeable Lithium-Ion Batteries

Lithium-rich layered oxides are among the most promising cathode candidates to build high-energy-density rechargeable Li-ion batteries but suffer from capacity/voltage fade, low reversibility, and poor rate capability. Herein, the synthesis and electrochemical application of heterostructured spinel/layered oxide (Li1.15Ni0.20Mn0.87O2) nanofibers as superior cathode materials are reported. The synergistic effect of 1D nanostructure and spinel/layer heterostructure enhances charge transfer, lithium diffusivity, and structural stability, resulting in improved initial Coulombic efficiency (approximate to 100%), rate performance (150 mAh g(-1) at 5C), and cyclability (258 mAh g(-1) after 70 cycles). In situ X-ray diffraction and Raman combined with first-principle calculations reveal that the spinel stabilizes the layered Li-rich Mn-based oxide structure via maintaining oxygen vacancy and suppressing the structural variation and oxygen overoxidation.