Fe掺杂P2型Na0.6Ni0.25Mn0.65Fe0.1O2微米片的制备与储钠性能研究

Sodium-ion batteries are expected to replace lithium-ion batteries as a new favorite in the field of energy storage due to their low cost and good safety, etc. P2 type Ni/Mn-based oxides have become a research hotspot in the field of sodium-ion battery cathode in recent years due to their tunable crystal structure, high theoretical specific capacity, and fast Na+ migration coefficient, etc. However, the irreversible structural transformation and Jahn-Teller lattice distortion, which are prone to occur during the charging and discharging process, seriously affect the cycling reversibility and structural stability, and become the main technological bottlenecks restricting their large-scale commercialization. To address the above problems, Fe-doped P2-type Na0.6Ni0.25Mn0.65Fe0.1O2 micro-sheets were prepared by PEG-assisted co-precipitation and used as cathode materials for sodium-ion batteries. It was found that Fe doping suppressed the change of oxidation state of manganese ions in the material and enhanced the discharge capacity and structural stability. Electrochemical tests showed that the Fe-doped electrode had the initial discharge capacity of up to 142 mAh g-1 at 0.2 C current density, a capacity retention of up to 93.3 % after 100 turns of cycling, and a capacity retention of 74.6 % under 500 turns of long cycling, demonstrating excellent electrochemical performance.