SiO2/Co encapsulated in N-doped carbon nanofibers as anode materials for lithium-ion batteries

Abstract

To address the issues of poor electrical conductivity and volume expansion of SiO₂, the composite SiO₂/Co encapsulated in N-doped Carbon nanofibers is prepared in situ using an electrostatic spinning method followed a high-temperature treatment. Co nanoparticles exist as an elementary substance in the composite and improve the electrical conductivity of the composite, resulting in enhanced electrochemical performance. In addition, the N-doped carbon nanofibers wrap around the outside of SiO₂/Co to form a conductive network, which improves the conductivity of the composite and alleviates the volumetric effects during the charge-discharge process. As expected, the prepared SiO₂/Co@N-doped carbon nanofibers exhibit excellent rate performance, which can provide a very high discharge specific capacity of 1276 mA h g⁻¹ and 493 mA h g⁻¹ at current densities of 0.1 A g⁻¹ and 2 A g⁻¹, respectively. The composite also has a long cycle life, with a reversible discharge capacity of 659 mA h g⁻¹ at 0.5 A g⁻¹ after 400 cycles, and 552 mA h g⁻¹ at 1 A g⁻¹ after 1000 cycles. Furthermore, a full-cell LiFePO₄||SiO₂|Co@N-doped carbon nanofibers can release a reversible capacity of 119 mA h g⁻¹ at 0.1C.