Dual-phase modulation via Mo doping and Li3PO4 coating for stabilized LiNi0.9Mn0.07Co0.02Al0.01O2 cathodes in high-energy lithium-ion batteries

Abstract

High-nickel layered oxide cathodes (Ni ≥ 90%) offer high capacity and energy density but face challenges like structural degradation and capacity fading during prolonged cycling. Herein, we report a novel Mo-doped LiNi0.9Mn0.07Co0.02Al0.01O2 (Mo-NMCA) cathode coated with Li3PO4 (LPO) nanoscale coating, synthesized via an optimized co-precipitation and solid-state method for the first time. The Mo doping enhances structural stability by mitigating transition metal migration, while the LPO coating improves interfacial stability and ionic conductivity. The synergistic influence of doping and coating is specifically comprehended by neutron diffraction and scanning transmission X-ray microscopy analyses. Electrochemical analysis reveals that LPO-Mo-NMCA demonstrates an initial discharge capacity of 219 mA h g-1 at 0.1 C and 176 mA h g-1 at 1 C with a capacity retention of 87 % after 200 cycles. At a high C-rate of 3 C, the cathode retains 91 % of its initial capacity after 200 cycles, showcasing exceptional rate capability and cycling stability. Furthermore, we made a pouch-type full cells with LPO-Mo-NMCA and a graphite anode achieved an initial discharge capacity of 218 mA h g-1 at 0.1 C, with 85 % capacity retention after 110 cycles. At a 3 C rate, these cells maintained 89 % capacity retention over 200 cycles in the voltage range of 2.0 to 4.2 V. These findings highlight LPO-Mo-NMCA as a promising cathode material for next-generation lithium-ion batteries, bridging the gap between high energy density and long-term cycling stability.