Oak Ridge National Laboratory, USA
Debasish Mohanty has obtained his PhD in Chemistry from University of New Orleans, USA, in 2011, and currently, he is a R&D Staff in Energy and Transpiration Science Division at Oak Ridge National Laboratory. His current research is focused on understanding the structure and structural degradation mechanism(s) in lithium-ion battery electrodes by applying materials diagnostic techniques such as neutron scattering, x-ray, microscopy, and magnetization. He is also conducting research that deals with non-destructive quality control (QC) evaluation of lithium-ion battery electrodes by employing laser caliper and IR thermography. He has vast experience in oxide (nano) materials synthesis and characterizing the oxide materials for several technological applications
As power requirements in all-electric vehicles (EVs) become more demanding, lithium ion battery (LIB) technology is expected to provide higher energy density. Implementation of high capacity and high-voltage electrodes would enhance the energy density of current LIBs. Layered lithium-manganese rich composite oxides (LMR) are identified as promising cathodes in high-energy density LIBs for EVs because of their ability to deliver high capacity (~240 mAh/g) and can be operated at high operating voltage (~4.7 V). However, practical usage of these electrodes are not feasible because of, i) first cycle irreversible capacity loss during high-voltage charging, ii) impedance rise during high-voltage hold, and iii) voltage fade after subsequent cycle which are mainly caused by structural degradation in the host LMR oxide. This presentation will focus on the findings to rationalize the structural degradation pathways in high-voltage LMR oxides by utilizing ORNL’s state-of-the-art advanced materials diagnostic to unravel the i) oxygen release process during high-voltage charging, ii) lithium/nickel crystallographic site interchange during high-voltage hold, and iii) cation migration after subsequent cycling causing phase transformation.