Synergistic Effect of Co ‐Mo Pinning in Lay‐Structured Oxide Cathode for Enhancing Stability toward Potassium‐Ion Batteries

The [Mn-Co-Mo]O6 octahedra are introduced into P3-K0.45MnO2 to optimize the local electron structure. The [MoO6] propose an empty outermost electrons (4d05s0) orbitals structure and the smaller ionic radius and higher oxidation state can induce a second-order JTE distortion in the adjacent [MnO6] octahedra. Co3+ do not induce Jahn-Teller effects due to the empty electron in eg orbital. AbstractOwing to the high economic efficiency and energy density potential, manganese-based layer-structured oxides have attracted great interests as cathode materials for potassium ion batteries. In order to alleviate the continuous phase transition and K+ re-embedding from Jahn-Teller distortion, the [Mn-Co-Mo]O6 octahedra are introduced into P3-K0.45MnO2 herein to optimize the local electron structure. Based on the experimental and computational results, the octahedral center metal molybdenum in [MoO6] octahedra proposes a smaller ionic radius and higher oxidation state to induce second-order JTE (pseudo-JTE) distortion in the adjacent [MnO6] octahedra. This distortion compresses the [MnO6] octahedra along thec-axis, leading to an increased interlayer spacing in the K+ layer. Meanwhile, the Mn3+/Mn4+ is balanced by [CoO6] octahedra and the K+ diffusion pathway is optimized as well. The proposed P3-K0.45Mn0.9Co0.05Mo0.05O2 cathode material shows an enhanced cycling stability and rate performance. It demonstrates a high capacity of 80.2  mAh g−1 at 100  mAh g−1 and 77.3  mAh g−1 at...
Source: Small - Category: Nanotechnology Authors: Tags: Research Article Source Type: research