The origin of heavy element doping to relieve the lattice thermal vibration of layered materials for high energy density Li ion cathodes

摘要: To achieve high energy density in Li-ion batteries, the limit of lithium extractable from layered structure cathodes needs to be increased, which can realized by raising cut-off potential. However, repeated charge/discharge up a voltage typically generates spinel phase parent structures and thereby deteriorates their electrochemical performances. There have been few effective strategies date solve this problem. After systematic review on doping reported, we that many heavy element dopants including 5d transition metals, lanthanides p-block elements favor structural stability crystal. Here, offer comprehensive study Sn-doped LiCoO2 reveal how these heavy-element contribute especially at charging voltages involving detrimental deintercalation. The introduction Sn dopant pin lattice vibration cathode stabilizes CoO6 octahedra against irreversible transformation into cubic under high-voltage operation over extended cycling. Further analyses based Debye theory suggest relief thermal must common feature unless bonding characters are significantly changed. precise investigation here shows clearly detailed role LiCoO2, providing new insight innovating performance cathodes.