Şarjedilebilir pillerde kullanılan elektrotların synchrotron radyasyonu ile karakterize edilmesi

In this Ph.D. thesis, the effects of Co and Ni substitution on Mn sites on the electrochemical performance of Na0.44MnO2 nanorod were investigated. In recent years, nanomaterials have been at the forefront of rechargeable sodium-ion battery technology and currently have a significant role in the commercialization of Na-ion batteries. The Na0.44MnO2 has a tunnel type nanorod structure which provides unique advantages such as short diffusion distance and large reaction surfaces. On the other hand, there are disadvantages besides the advantages of this crystal structure: crystal structure degradation due to structural stress and Jahn-Teller effect on Mn sites in long charge/discharge cycles. In this study, it is aimed to prevent structural degradation and increase battery performance by making Co and Ni substitution to the Mn regions of Na0.44MnO2 nanorods. During the research, physical and electrochemical analysis of all samples were carried out in detail. Especially, unique advantages of synchrotron radiation have been used to better understand the changes in the crystal structures. As a result of this study, it was found that the 0.1% and 0.5% nickel and 0.1% cobalt substituted samples had nanorod form and higher capacity retention than Na0.44MnO2.