Enhancing the Structural Stability of LiCoO₂ at Elevated Voltage via High-Valence Sb Doping

Abstract

Elevating the charging cutoff voltage of lithium cobalt oxide (LiCoO 2 ) batteries to 4.6 V (vs Li/Li + ) enables the attainment of an impressive specific capacity; however, this advancement is hampered by severe structural degradation above 4.45 V attributed to unfavorable phase transitions and the occurrence of undesirable side reactions. Herein, we introduce high-valence Sb 5+ into LiCoO 2 , suppressing the O3 to H1−3 phase transition and thereby enhancing the structural stability of LiCoO 2 . The stable structure not only enables the formation of a more stable cathode-electrolyte interphase film on the surface of LiCoO 2 but also suppresses the dissolution of Co, reducing surface side reactions. As a result, Sb-doped LiCoO 2 , serving as a 4.6 V anode, exhibited a remarkable specific capacity of 169.2 mAh g −1 at a current density of 1C, with a durable capacity retention of 83.2% after 100 cycles. This study offers a structural modulation strategy for the further advancement of high-voltage LiCoO 2 cathodes.

Regenerated Ni-Doped LiCoO2 from Spent Lithium-Ion Batteries as a Stable Cathode at 4.5 V

“…The distinct splitting of the (006)/(012) and (018)/(110) peaks in the patterns indicates a well-developed layered structure of the samples. In comparison to RLCO, the (003) diffraction peak of LC 0.95 N 0.05 O shifts to a lower degree, indicating the successful doping of Ni elements in LCO. , Raman analysis conducted on all regenerated LCO samples further confirms the ordered layered lattice structure. The characteristic E g and A 1g peaks of LCO correspond to the bending and stretching vibrations of the O–Co–O bonds and Co–O bonds, respectively .…”