Dual Co/Li slabs anchoring and surface nano-passivation: toward a stable 4.6 V operation of LiCoO₂ cathode with enhanced lattice structure

Lithium cobalt oxide (LiCoO₂, LCO) is a widely used cathode material for lithium-ion batteries in portable electronic devices. However, its application at high voltages of 4.6 V is severely restricted due to crystal lattice collapse and uncontrollable interface reactions. To address these challenges, an innovative design of LCO combined with Co/Li dual slab regulation and nanostructured Li₄Ti₅O₁₂ (LTO) surface passivation, termed as 0.4 %LTO@LMCLO, has been proposed to achieve a high-energy/power-density and structurally stable cathode material. The incorporation of La and Mg elements respectively into the Co and Li slabs expands the (0 0 3) crystal planes via controlling the pre-sintering temperature, thereby reinforcing the layered crystal lattice of LCO. This enhancement enables the material to support more cycles and faster charge/discharge capabilities within the 3.0–4.6 V range. Notably, the lattice oxygen in 0.4 %LTO@LMCLO is effectively restrained through both internal and external integration, significantly inhibiting the escape of O₂. Moreover, the nanostructured LTO creates a stable microenvironment interface for the electrolyte due to its lower lithiation potential, thereby reducing the release of CO₂ caused by solvent redox reactions. As a result, the designed 0.4 %LTO@LMCLO cathode exhibits a high specific capacity of 213 mAh g⁻¹ at 0.1C and 189 mAh g⁻¹ at 5C. It also demonstrates excellent cycle stability, with 89 % capacity retention after 100 cycles at a high operating voltage of 4.6 V and 1C. These findings provide valuable insights for the construction of stable layered cathode material structures.