Dual-Porosity\nSiO₂/C Nanocomposite with\nEnhanced Lithium Storage Performance

Abstract

Mesoporous\nSiO₂ nanospheres (MSNs) and carbon nanocomposite\nwith dual-porosity structure (DMSNs/C) were synthesized via a straightforward\napproach. Both MSNs and DMSNs/C showed uniform pore size distribution,\nhigh specific surface area, and large pore volume. When evaluated\nas an anode material for lithium ion batteries (LIBs), the DMSNs/C\nnanocomposite not only delivered an impressive reversible capacity\nof 635.7 mAh g^–1 (based on the weight of MSNs in\nthe electrode material) over 200 cycles at 100 mA g^–1 with Coulombic efficiency (CE) above 99% but also exhibited excellent\nrate capability. The significant improvement of the electrochemical\nperformance was attributed to synergetic effects of the dual-mesoporous\nstructure and carbon coating layer: (i) the dual-porosity structure\ncould increase the contact area and facilitate Li⁺ diffusion\nat the interface between the electrolyte and active materials, as\nwell as buffer the volume change of MSNs, and (ii) the homogeneous\ncarbon coating represented an excellent conductive layer, thus significantly\nspeeding the lithiation process of the MSNs significantly, while further\nrestraining the volume expansion. Considering the facile preparation\nand good lithium storage abilities, the DMSNs/C nanocomposite holds\npromise in applications in practical LIBs.