The highest energy density cathode materials are currently found among the layered compounds based on Ni,Co and Mn, but achieving much more than 200mAh/g has become difficult. Two new ideas are promising to obtain substantially higher cathode capacity: 1) By using a substantial amount of Li-excess, cathodes can be made tolerant to metal disorder thereby enabling the use of a much larger group of transition metals, while achieving capacities well above 200 mAh/g. 2) Reversible redox process that take place on the oxygen ions rather than on the transition metal ions are now well established and can reduce the transition metal content of cathode compounds. Join Professor Gerbrand Ceder at his talk at the 18th International Meeting on Lithium Batteries as he explores the physics of both these new directions and demonstrates with several examples how they have enabled novel high-capacity cathodes.
View his slides here or on the presentations page and associated papers and our other publications on the publications page. Associated papers listed on slide 2 of the presentation are available here:
Oxygen redox activity
D.-H. Seo,† J. Lee,† A. Urban, R. Malik, S. Kang, G. Ceder, Nature Chem., Advance Online Publication (2016): The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials
Percolation in cation-disordered structures
Covalency and hybridization of the TM-3d and O-2p in layered cathodes
D.-H. Seo et al. Physical Review B, 92, 115118 (2015): Calibrating transition-metal energy levels and oxygen bands in first-principles calculations: Accurate prediction of redox potentials and charge transfer in lithium transition-metal oxides
Electronic Structure effects on Transition Metal Migration