Uniform Na⁺ Doping-Induced Defects in Li- and Mn-Rich Cathodes for High-Performance Lithium-Ion Batteries

The corrosion of Li- and Mn-rich (LMR) electrode materials occurring at the solid-liquid interface will lead to extra electrolyte consumption and transition metal ions dissolution, causing rapid voltage decay, capacity fading, and detrimental structure transformation. Herein, a novel strategy is introduced to suppress this corrosion by designing an Na⁺-doped LMR (Li_1.2Ni_0.13Co_0.13Mn_0.54O₂) with abundant stacking faults, using sodium dodecyl sulfate as surfactant to ensure the uniform distribution of Na⁺ in deep grain lattices-not just surface-gathering or partially coated. The defective structure and deep distribution of Na⁺ are verified by Raman spectrum and high-resolution transmission electron microscopy of the as-prepared electrodes before and after 200 cycles. As a result, the modified LMR material shows a high reversible discharge specific capacity of 221.5 mAh g^-1 at 0.5C rate (1C = 200 mA g^-1) after 200 cycles, and the capacity retention is as high as 93.1% which is better than that of pristine-LMR (64.8%). This design of Na⁺ is uniformly doped and the resultanting induced defective structure provides an effective strategy to enhance electrochemical performance which should be extended to prepare other advanced cathodes for high performance lithium-ion batteries.