Perovskite-coated small-size single-crystalline W-doped Ni-rich cathodes with greatly enhanced power density for Li-ion batteries

Abstract

Single-crystalline Ni-rich Co-poor cathodes with high safety and competitive cost have recently attracted widespread attention, yet they still suffer from poor rate capability owing to the long Li-ion transfer path. Herein, a small-size (∼2.01 μm) single-crystalline LiNi_0.85Co_0.05Mn_0.10O₂ cathode with high power and superior stability is designed and synthesized by in situ introducing W-doping and perovskite La₄NiLiO₈ coating. The W-doping in high-temperature lithiation can obviously decrease the size of single-crystalline Ni-rich cathodes with high dispersion compared with the conventional strategy by directly doping W into NCM cathodes (∼3.09 μm). The perovskite coating layer has a high ion-conductivity and stable crystal structure, greatly enhancing the Li-ion diffusion rate and interfacial chemical stability. As a consequence, the as-obtained single-crystalline cathodes deliver a high reversible specific capacity of 213.6 mA h g⁻¹ at 0.1C and 111.8 mA h g⁻¹ even at 10C in coin-type half-cells. After assembled into pouch-type full-cells with commercial graphite anodes, a durable cycling retention of 89.6% is obtained after 1000 cycles at 1C within 2.7–4.3 V. This work proves a way for developing high-power and stable single-crystalline Ni-rich cathodes.