Although the silicon oxide (SiO2) as an anode material shows potential and promise for lithium-ion batteries (LIBs), owing to its high capacity, low cost, abundance, and safety, severe capacity decay and sluggish charge transfer during the discharge–charge process has caused a serious challenge for available applications. Herein, a novel 3D porous silicon oxide@Pourous Carbon@Tin (SiO2@Pc@Sn) composite anode material was firstly designed and synthesized by freeze-drying and thermal-melting self-assembly, in which SiO2 microparticles were encapsulated in the porous carbon as well as Sn nanoballs being uniformly dispersed in the SiO2@Pc-like sesame seeds, effectively constructing a robust and conductive 3D porous Jujube cake-like architecture that is beneficial for fast ion transfer and high structural stability. Such a SiO2@Pc@Sn micro-nano hierarchical structure as a LIBs anode exhibits a large reversible specific capacity ~520 mAh·g−1, initial coulombic efficiency (ICE) ~52%, outstanding rate capability, and excellent cycling stability over 100 cycles. Furthermore, the phase evolution and underlying electrochemical mechanism during the charge–discharge process were further uncovered by cyclic voltammetry (CV) investigation.
Silica
(SiO2) is considered as a promising candidate
anode material for next-generation lithium-ion batteries (LIBs) owing
to its low cost, abundant reserve on Earth, and relatively high theoretical
specific capacity. However, the development of SiO2-based
anode materials has been impeded by their poor electrical conductivity
and sluggish charge-transfer kinetics. Herein, porous SiO2/tin (SiO2@Sn) composites with tunable SiO2 to Sn molar ratios are fabricated using a scalable, simple, and
low-cost ball-milling and low-temperature thermal-melting combined
method. It is found that the Sn phase can significantly improve the
diffusion and migration kinetics of Li in the composites, whereas
the SiO2 to Sn molar ratio plays a key role in the mechanical
integrity and subsequent cycling behaviors of the composite electrodes.
By optimizing the molar ratio of SiO2/Sn to 10:1, the synergistic
effect of Li storage between SiO2 and Sn can lead to the
simultaneous achievement of improved Li kinetics and ensured mechanical
integrity, contributing to the excellent electrochemical performance
of the composite with a large reversible capacity of 613 mAh g–1 at 100 mA g–1, a remarkable rate
capability of 450 mAh g–1 retained at 1000 mA g–1, and long-term cycling durability with ∼95%
capacity retention over 200 cycles.
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