W-incorporated high-performance layered cathode materials for advanced lithium-ion batteries

High-nickel cobalt-free cathode materials are regarded as some of the promising candidates for high-energy-density lithium-ion batteries due to their excellent attributes of high capacity and cost-effectiveness. However, increasing the nickel content and removing cobalt lead to degradation of the electrode-electrolyte interfacial environment and other bulk-phase layered structure issues, which significantly compromise the battery's cycle life. In this work, a W-doped LiNi_0.90Mn_0.07Al_0.03O₂ cathode material was synthesized by introducing a small amount (2 mol%) of tungsten (W) during the lithiation procedure. The W-doping enhanced the cyclic stability of the LiNi_0.90Mn_0.07Al_0.03O₂ cathode (capacity retention after 100 cycles: 90.82% <i>vs.</i> 88.99% for the pristine material at 4.3 V) remarkably. These improvements are attributed to the high-valence W⁶⁺ passivating the cathode material surface activity, thereby stabilizing the bulk structure and electrode-electrolyte interface. These findings provide valuable strategic insights for developing high-nickel, cobalt-free cathode materials in lithium-ion batteries.