Superior Lithium Storage Capacity of α-MnS Nanoparticles Embedded in S-Doped Carbonaceous Mesoporous Frameworks

Herein, a Mn-based metal-organic framework is used as a precursor to obtain well-defined alpha-MnS/S-doped C microrod composites. Ultrasmall alpha-MnS nanoparticles (3-5 nm) uniformly embedded in S-doped carbonaceous mesoporous frameworks (alpha-MnS/SCMFs) are obtained in a simple sulfidation reaction. As-obtained alpha-MnS/SCMFs shows outstanding lithium storage performance, with a specific capacity of 1383 mAh g(-1) in the 300th cycle or 1500 mAh g(-1) in the 120th cycle (at 200 mA g(-1)) using copper or nickel foil as the current collector, respectively. The significant (pseudo)capacitive contribution and the stable composite structure of the electrodes result in impressive rate capabilities and outstanding long-term cycling stability. Importantly, in situ X-ray diffraction measurements studies on electrodes employing various metal foils/disks as current collector reveal the occurrence of the conversion reaction of CuS at (de)lithiation process when using copper foil as the current collector. This constitutes the first report of the reaction mechanism for alpha-MnS, eventually forming metallic Mn and Li2S. In situ dilatometry measurements demonstrate that the peculiar structure of alpha-MnS/SCMFs effectively restrains the electrode volume variation upon repeated (dis)charge processes. Finally, alpha-MnS/SCMFs electrodes present an impressive performance when coupled in a full cell with commercial LiMn1/3Co1/3Ni1/3O2 cathodes.