Study And Modification Of Layered Oxide Cathode Materials Of Sodium Ion Battery

The development of lithium-ion batteries（LIBs）has been limited because of high price.Na-ion batteries（NIBs）are highly likely to replace LIBs in the next generation due to their low price and wide distribution of elements.It is a key problem to be solved urgently in the industrial application of NIBs that the irreversible volume changes of cathode before and after the cycle,leading to the deterioration of cycle performance.Currently,cathode materials include layered cathode oxides,Prussian blue compounds,polyanions,etc.,the layered cathode oxides have attracted wide attention due to their advantages of high energy density,simple preparation method,adjustable voltage window and so on.Improving the cycle performance of SIBs has been the focus of research.It is also the key to achieving large-scale industrialization of SIBs.To develop high-capacity and long-cycle cathode materials,a series of modification strategies for Na Ni_0.4Cu_0.1Mn_0.4Ti_0.1O₂（NCMT）are proposed in this paper,including preparation method,material composition,and interface improvement.We synthesis of high capacity,long cycling of Na Ni_0.35Mg_0.05Cu_0.1Mn_0.4Ti_0.1O₂（NCMT-Mg）cathode material,with high ionic conductivity and high capacity retention Na Mg PO4@Na Ni_0.4Cu_0.1Mn_0.4Ti_0.1O₂（NMP@NCMT）.NCMT-Mg showing a high reversible specific capacity of 165 m Ah g^-1 in the voltage range of 2.4-4.3V.The reversible specific capacity of 111 m Ah g^-1 remains,with a capacity retention of 67.3%,an improvement of about 13%over the NCMT after 350 cycles at 0.1C.NMP@NCMT exhibits high capacity and excellent cycle life in the full-cell.The high voltage cyclic stability mechanism of the cathode was systematically characterized,providing an important reference for developing high performance NIBs.