Research Projects

The practical deployment of anionic redox for high-capacity sodium ion batteries (SIBs) is impeded by irreversibility and associated structural degradation, which compromise cycling stability. The fundamental mechanisms governing these processes remain poorly understood. In this regard, the central challenge and the critical need are to design cathode materials that possess reversible anionic redox and achieve a unified and fundamental understanding and rational stabilization of anionic redox in Na-based layered oxides. Without addressing this, high-capacity SIBs are unlikely to become practical or commercially viable. To address this, the proposed project adopts an integrated computational-experimental approach to design high-capacity cathode materials with reversible anionic redox and unravel a unified mechanism and the underpinning physics of anionic redox in layered sodium-based transition metal oxides. Computationally, we will use density functional theory (DFT) to screen dopants and multi-component layered cathode materials, followed by ab-initio molecular dynamics (AIMD) and machine-learned interatomic potentials (MLIPs) to model key degradation pathways such as oxygen release, cation migration, and defect/cation dynamics. Surface and interface processes will be probed using AIMD and MLIP-based molecular dynamics simulations to assess the stability of active oxygen species under cycling conditions. Complimentary experiments will involve operando X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Raman spectroscopy, differential electrochemical mass spectrometry (DEMS), and transmission electron microscopy (TEM), to examine structural changes, electrochemical properties, and oxygen redox during electrochemical cycling. Electrochemical characterization (voltage profiles, cycling performance, rate capability) will be used to validate theoretical predictions and assess practical viability. The novelty of this work lies in the synergistic use of theory and multiple in situ and ex-situ experiments to build a mechanistic understanding of reversible anionic redox in high-capacity Na-ion batteries. The insights gained will enable the rational design of high-capacity, structurally stable SIB cathodes, thereby paving the way for next-generation sustainable energy storage technologies. Finally, high capacity and stable ‘layered’ Na-TM-oxide cathode materials, Na-ion ‘full’ cells will be developed in the form of 2-3 Ah prototypes, exhibiting energy density of greater than 200 Wh/kg and having above 80% capacity retention at least for 1000 cycles.