High-capacity MoS2@PDMAEMA-Li+ nanoscrolls for advanced lithium batteries: Design, experimental study, and theoretical validation

Abstract

A new approach to the controlled synthesis of polymer/inorganic nanocomposite of poly(dimethylaminoethyl methacrylate) (PDMAEMA) coated MoS₂ nanoscrolls containing electrostatically bound Li ⁺ cations within the polymeric shell is considered. The method is based on the adsorption of Cu²⁺ coordinated metal complex molecules onto MoS₂ nanoparticle surfaces, followed by surface-initiated radical graft polymerization of PDMAEMA, yielding scrolled core–shell nanostructures. The PDMAEMA shell effectively immobilizes Li⁺ ions via coordination with nitrogen atoms in tertiary amino groups. Structural and physicochemical characterization by TEM, DLS, XRD, SAXS, elemental analysis, and electrochemical impedance spectroscopy (EIS) confirms the formation and effectiveness of the nanocomposites. Systematic variation of MoS₂ core morphology and PDMAEMA–Li ⁺ shell thickness enables tuning of electrochemical performance. Monodisperse and stable MoS₂ cores with an average diameter of ∼75 nm were obtained at pH 7.8. The dependence of Gibbs’ energy changes of the intercalation reaction on the coating thickness was studied. The nanocomposites exhibit Li⁺ diffusion coefficients (∼10⁻¹² cm² s⁻¹), which are nearly one order of magnitude higher than those of pristine MoS₂. The specific capacity of the optimized nanocomposite with shell thickness of 45.4 Å reaches 5339 mA h g⁻¹, significantly exceeding that of pristine MoS₂ (2769 mA h g⁻¹). This enhancement is attributed to the encapsulating polymeric shell, which increases the interfacial potential barrier and thus eliminates surface states under the Fermi level. Fermi–Dirac based theoretical approximation supports this mechanism, indicating that the elimination of these surface states can nearly double the discharge capacity, in agreement with experimental data. These findings offer a promising strategy for the rational design of next-generation high-performance materials for lithium-ion batteries.