High Energy Next Generation Electrode for Li-ion Batteries

This thesis focuses on the synthesis and characterization of manganese based cation disordered rock salt cathodes for lithium-ion battery applications. Manganese based cation disordered rock salt cathodes are synthesized by mechanosynthesis and then structurally and electrochemically analysed. Chapter 1 provides a general overview of lithium-ion batteries and a detailed reading of their working principles and the cathode materials used. Chapter 2 presents detail the methods used to obtain and analyse the materials synthesized in this thesis, as well as the fundamental principles for understanding the main techniques used to investigate their properties. Chapter 3 focuses on the mechanochemical synthesis of Li2MnO3-xFx, which involves the partial substitution of fluorine into oxygen. The mechanochemical synthesis of the Li2MnO3-xFx (x=0, 0.2, 0.8, 1, 1.2) compositions were examined, along with muon-spin spectroscopy. Chapter 4 focuses on Li2MnO2F cation disordered rock salt cathode. This includes the optimization of parameters such as ball milling duration and selection of starting materials to achieve the desired capacities, alongside comprehensive analysis of the structural, morphological, and electrochemical properties of the synthesized material. Also, it involved the careful selection of binder particle size and the optimization of electrode ratio to improving capacity and enhancing stability during cycling. Chapter 5 presents to demonstrate the mechanochemical synthesis of Li2Mn1-yZryO2F, doping the Zr-cation in place of some manganese. The crystal structure was studied by X-ray diffraction (XRD) prior to electrochemical analysis where coin cells were assembled and galvanostatic cycling performed. Chapter 6 gives a general overall conclusion and future work. Chapter 7 includes the Appendix information.