**2.3 Multi (mixed cationic and anionic) redox in chalcogen cathode for Li-ion batteries**

In order to improve the metal-ligand covalency by substituting a lower electronegative chalcogen ligand such as sulfur in the cathode. In this case, reversible mixed anionic and cationic redox occurs by the metal d band penetrates into the ligand p band. The partially filled d orbital redox couples like Fe2+/3+ are introduced in the Li-ion conducting phase (Li2SnS3) is the development of a new family of layered structured cathode materials. Investigation of high-resolution transmission electron microscopy and high annular dark field-scanning transmission electron microscopy reveals that the multi-redox structural modifications and nanopore formation on its surface, during cycling process. In this study, Ni, Co ions free cathodes using various functional materials in the chalcogen-based dual anionic and cationic redox cathodes.
