Dual-Porosity SiO₂/C Nanocomposite with Enhanced Lithium Storage Performance

Abstract

Mesoporous SiO2 nanospheres (MSNs) and carbon nanocomposite with dual-porosity structure (DMSNs/C) were synthesized via a straightforward approach. Both MSNs and DMSNs/C showed uniform pore size distribution, high specific surface area, and large pore volume. When evaluated as an anode material for lithium ion batteries (LIBs), the DMSNs/C nanocomposite not only delivered an impressive reversible capacity of 635.7 mAh g–1 (based on the weight of MSNs in the electrode material) over 200 cycles at 100 mA g–1 with Coulombic efficiency (CE) above 99% but also exhibited excellent rate capability. The significant improvement of the electrochemical performance was attributed to synergetic effects of the dual-mesoporous structure and carbon coating layer: (i) the dual-porosity structure could increase the contact area and facilitate Li+ diffusion at the interface between the electrolyte and active materials, as well as buffer the volume change of MSNs, and (ii) the homogeneous carbon coating represented an excellent conductive layer, thus significantly speeding the lithiation process of the MSNs significantly, while further restraining the volume expansion. Considering the facile preparation and good lithium storage abilities, the DMSNs/C nanocomposite holds promise in applications in practical LIBs.