Executive Summary : | Electrochemical energy storage devices like Li-ion batteries (LIBs) are crucial in the 21st century empowering myriads of portable electronic devices, plug-in (hybrid) electric vehicles and grid power storage. However, the exponential consumption of Co-based cathodes has raised concerns over the net cost and toxicity of LIBs. As Co-based minerals are scarce and unevenly distributed across the globe, the cost of Li-ion batteries has risen manifold. Further, it can trigger geo-political tension. In this scenario, various economic and ecological Co-free cathode materials can offer viable alternatives, where Mn-, Ni- and Ti-based chemistry can be implemented to design low cost high energy density battery electrode materials. For (hybrid) electric vehicle applications demanding high energy density, high-voltage Co-free spinel electrodes can serve as economically viable option. In future, discovery and development of Co-free cathode materials hold key for sustainable battery application. The current project focuses on fundamental investigation of Co-free spinel family of electrode materials with attention to: (a) Ni-based spinel LiNi0.5Mn1.5O4 as high-voltage cathode, and (b) Ti-based spinel Li4Ti5O12 as 1.45 V anode. The core theme of this project will be ‘Co-free spinel electrode materials’. It revolves around ‘synthesis-structure-electrochemistry’ of spinel materials. Apart from conventional solid-state synthesis, various solvothermal synthesis routes will be employed to produce spinel materials with tuneable particle size (from nano to micro) and morphology. It will be followed by in-depth crystal and magnetic structure analyses combining lab-XRD, synchrotron XRD, solid-state NMR spectroscopy, XPS spectroscopy and variable temperature neutron powder diffraction. Finally, electrochemical characterization of these electrode materials will be conducted using suites of electroanalytical tools. The major scientific objectives will be: (a) Implementation of energy-savvy synthesis of spinel based electrodes (LiNi0.5Mn1.5O4 and Li4Ti5O12), (b) In-depth structural analysis of these spinels during reversible Li-(de)insertion process to gauge the electrochemical redox mechanism, (c) To perform electrochemical optimization to extract maximum capacity/ energy density, and (d) To implement Ni-based and Ti-based spinels to demonstrate 18650-type full cell with stable cycling and high energy density. This project falls into fundamental research category that can lead to (a) academic training of PhD students, (b) discovery of structural modulation (ordering/ phase transition) in spinel cathode materials, (c) generating new structure/ electrochemical data on Co-free cathode materials, (d) demonstration of final battery prototypes, and (e) publication of research outcomes in internationally reputed journals and Indian Patents. |