Antimony-Doped Nickel-Rich Layered Oxides with Improved Cycling Stability toward High Lithium-Storage Performance Cathodes

Rapid capacity fade and structural deterioration are common obstacles to the commercial applications of nickel-rich layered oxide cathodes (Ni ≥ 90%). To address this, we synthesized an antimony(Sb)-doped LiNi_0.9Co_0.05Mn_0.05O₂ cathode with enhanced structural stability and superior capacity retention using a simple high-temperature solid-state method. Antimony is immobilized within the crystal lattice, thus reducing Li/Ni disorder and improving the H2-H3 phase change reversibility. The relatively large radius of Sb³⁺ (0.076 nm) gives rise to a widening of the c-axis lattice spacing, which in turn accelerates Li⁺ diffusion. The Sb-O bond effectively mitigates lattice oxygen loss, thereby enhancing structural stability. Therefore, the 0.2% Sb-doped LiNi_0.9Co_0.05Mn_0.05O₂ cathode (0.2Sb-NCM) exhibits an impressive capacity of 202.71 mAh/g at 0.1C and 137.64 mAh/g at 10C. Moreover, the 0.2Sb-NCM shows excellent cycle stability, maintaining capacity retention of 94.57% at 1C after 100 cycles, while LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90) retains only 87.78%. Additionally, the capacity retention at 2C is notably enhanced, rising from 50.46% for NCM90 to 80.5% for 0.2Sb-NCM after 200 cycles. This work offers a facile method for large-scale applications of nickel-rich cathodes with enhanced cycle stability in lithium-ion batteries.