Achieving Excellent Electrochemical Stability of Li-rich Mn-Based Cathode by One-Step Decanoic Acid Treatment Under...

High-capacity layered Li-rich Mn-based oxides (LLMO) materials suffer irreversible lattice oxygen loss, voltage decay, and rapid capacity decay during the cycling process, which severely hinder their practical application. This study proposes a one-step decanoic acid treatment strategy without further process (i.e., sintering, washing, etc.), to modify the near-surface of Li-rich Mn-based materials (Li_1.2Mn_0.54Ni_0.13Co_0.13O₂). The investigation reveals that decanoic acid preferentially neutralizes surface residual lithium and evenly adheres to the material surface. This subsequently participates in forming a thin and stable cathode electrolyte interphase (CEI) film and provides stable surface oxygen vacancies during cycling, effectively suppressing the electrode/electrolyte interfacial side reactions and improving the structural stability. Comparing with the pristine LLMO (270.6 mAh g^-1 initial capacity at 0.1 C, 68% capacity retention after 200 cycles at 1 C), the prepared DA-LLMO shows significantly enhanced discharge specific capacity and cycling stability (293.5 mAh g^-1 initial capacity at 0.1 C, 93% capacity retention after 200 cycles at 1 C). Furthermore, experimental results demonstrate that this method exhibits a certain degree of general applicability for other cathodes (LiCoO₂ and Ni-rich oxide). This work establishes a novel approach for near-surface design of high-energy-density lithium-ion batteries.