Abstract
Due to the sodium abundance and availability,sodium-ion batteries (SIBs) have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na0.67Ni0.33Mn0.67O2 cathode material.The combined analysis of ex-situ X-ray absorption fine structure (XAFS) spectroscopy,aberration-corrected high resolution transmission electron microscopy (AB-HRTEM) and X-ray diffraction (XRD) show that the strong Ti-O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na0.67Ni0.33Mn0.52Ti0.15O2 exhibits a reversible capacity of 89.6 mA h g-1 even at 5 C,an excellent cyclability with 88.78 ％ capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.
基金项目
国家自然科学基金(11705015)
国家自然科学基金(U1832147)
Science and Technology Plan Project of Suzhou(SYG201738)
Science and Technology Plan Project of Suzhou(SZS201710)
staff of the XAFS beamline of the Beijing Synchrotron Radiation Facility()
NETL
NSTL
万方数据