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

Elevating the charging cutoff voltage of lithium cobalt oxide (LiCoO2) 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 Sb5+ into LiCoO2, suppressing the O3 to H1-3 phase transition and thereby enhancing the structural stability of LiCoO2. The stable structure not only enables the formation of a more stable cathode-electrolyte interphase film on the surface of LiCoO2 but also suppresses the dissolution of Co, reducing surface side reactions. As a result, Sb-doped LiCoO2, 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 LiCoO2 cathodes.