Three‐In‐One Structural Design Enables High‐Stability Co‐Free Li‐Rich Cathodes

Abstract Co‐free Li‐rich Li 1.2 Ni 0.2 Mn 0.6 O 2 (LNM) exhibits the highest energy density among lithium‐ion batteries (LIBs) cathodes but suffers from severe phase transitions and inferior bulk conductivity. Herein, a three‐in‐one structural regulation involving the Li‐, Mn‐, and O‐sites using KPF 6 is designed. The three‐in‐one doping effect expands the Li interlayer spacing, increases the oxygen vacancy formation energy, strengthens the transition metal‐oxygen bonds, suppresses oxygen release, and comprehensively enhances structural stability. In situ measurements demonstrate the improved structural reversibility and stability. Density functional theory (DFT) calculations confirm that the enhanced conductivity, attributed to the increased electron cloud density near the Fermi energy and the availability of conduction bands for electron transition. Benefiting from the structural trinity‐design, the optimum sample can deliver a high capacity of 191.2 mAh g −1 (compared to 161.6 mAh g −1 for LNM) with an unparalleled 84% long‐term cycle stability (vs 79% for LNM) at 1C after 500 cycles. It also exhibits lowest voltage decay (0.676 V) compared with other samples during 500 cycles. Therefore, such a pioneering trinity strategy offers a valuable approach for designing high‐capacity LNM cathodes with ultra‐long service‐life.